Musty Smell Dirty Sock Syndrome

[milkman's daughter]

We have had to have our coil replaced the past two years in a row a few weeks after we go from cooling to heating. We have 2 UV lights shining on our coil at all times, no visible mold on coil, no visible mold in home, keep it clean and dusted fairly well, use 3M pleated filters. Try to keep the humidity down to 50 or lower.

Help, if anyone can suggest how to solve this please respond.

MMD

[drk]

Sorry somebody coned you in to buying two UV lights. Now take that 3m filter and put it in the trash and buy you a standard pleat. Have you had the coil cleaned? Is the smell only in heating mode?

[milkman's daughter]

Actually it was my idea, in desperation over this happening now for the 3rd yr. in a row, to get two lights. The odor comes now with the cooling cycle. The pleated filter is what we are using.

What type/brand filter do you recommend?

Thanks for responding,

MMD

[drk]

A 3 to 5 dollar pleat will work just fine!

[kcmk]

MMD, we have been having the same problems, since we replaced our old Bryant AC/coil with a new Trane in Aug '03.. Smell started Oct '04, Trane replaced coil with a second in Nov '04. It ran fine until this Oct '05. Now it's smelling again! I don't know what to do either. NO ONE seems to have an answer. We have had HVAC dealers, duct cleaners, mold remediation people, Trane reps., etc. all at our house....no one knows how it started nor how to fix it. Is your coil a Trane by any chance???

Kevin

[too tall terry]

there are special coils used to replace those that have been determined to have the dirty sock syndrome..the coils are teflon coated,and are designed to retard the growth...i have replaced 2 in only 15 years in the field,but it has solved the problem both times

[kcmk]

Originally posted by too tall terry
there are special coils used to replace those that have been determined to have the dirty sock syndrome..the coils are teflon coated,and are designed to retard the growth...i have replaced 2 in only 15 years in the field,but it has solved the problem both times

I have inquired with a Trane dealer about these coated coils. He is suppose to check with Trane and get back to me this coming week.

MMD, have you checked into these coated coils?

Kevin

[milkman's daughter]

No one has ever mentioned these coils to me. This may be because I have chemical allergies and they are afraid I will react to the teflon.

Mine is happening the same time of year as yours. I wonder how safe the teflon coil is re: doesn't seem like it would off gas any teflon in the cooling season, but would there be any problem in the winter?

I am so sick of thinking about the air handler and waiting every year for it to start over with the mold smell. There is never an visible mold showing (I may have said that before).

I don't think throwing away my filter and getting a cheap pleated filter will solve the problem.

Let me know about the teflon coil. I guess you or I would not know if it works if we get one put in, until next year at this time. This happens around Thanksgiving when we get a cold snap and have to freeze for days because it takes a while to get a new coil scheduled...

[milkman's daughter]

Not a trane, but a bryant...

[drk]

I don't think throwing away my filter and getting a cheap pleated filter will solve the problem.




[/B][/QUOTE]
No it will not fix the problem! But you will be closer to spect CFM

[milkman's daughter]

"closer to spect CFM"

I do not know what that means. Could it mean better air flow?

Thanks,

[milkman's daughter]

Kevin,

Is you unit a heat pump? Ours is. I am wondering if this is a problem that heat pumps have more than regular units. I've heard yes and no by dealers.

Also, the filter type. I've been told the filter is good and not impeding air flow (not by the seller of the filter).

Ghads

[too tall terry]

with DIRTY SOCK SYNDROME,homeowners will talk of an odor much like the smell of sweaty socks in a hamper,but this is usually during the defrost cycle,and not so much at the beginning of the heating season....you may simply be smelling the strip heaters burning off the summer build up that always tends to happen....to test this out,you might turn your t-stat to emergency heat setting and crank the heat all the way up,give the sequencers time to stage in the strip heaters and not only are you burning off any build up that might be present,you are also checking your back up/emergency heat...let the heat run for about 10-15 mins.,and any smelly build up should burn of for the heating season,also,the teflon coated coil is safe,....a good understanding of how and why a heat pump operates is critical to a home owner..i would suggest that you find a company in your area,and let them educate you....nothing meant by that all,it is just the more you know,the better off you are...good luck

[Edited by too tall terry on 11-13-2005 at 08:20 PM]

[classical]

In regards to the coated coils they are not treated with Teflon. The Technicoat coils use a phonelic coating which after a period of time will eventually cracks. The coating cracks because the coating has low elasticity properties and the expansion contraction of the material is less than the aluminum of the coil.

Bronz Glo coated coils use a material closer to rubber but still remains basically heat transparent. It has greater elasticity and will not crack. The Bronz Glo coated coils also have an anti-microbial mixed into the coating.

Contact Bronz-Glo in Florida and they can provide you with a contractor in your area that is an applicator. They also have spray cans of the coatings that can be applied with the coil in place by your local contractor. The spray cans are not as good as the immersed coil but it works fairly well.

[too tall terry]

i knew that someone would catch that,...i always call them teflon coated coils,but your post was very well stated,and i learned something or two...thanks

[milkman's daughter]

No offense taken, and we will try this. What happens is this. The weather turns cold and we start using the heater. It can take a few weeks, but as we use the heat, the smell starts and it is nasty mold smell, and has not gone away in the past two years until we replace the coil.

I've spoken with so many dealers/companies and no one has suggested what you did about turning the emergency heat on and we will try that.

What is your though on using the lesser filtering filter?

_____________________________________

"No snowflake in an avalanche ever feels responsible"

[milkman's daughter]

To your knowledge can coils coated in this material withstand UV Lights?

Will call company.

[classical]

To some extent they can withstand the "UV" rays but the rays will eventually break down any petrochemical product.


"UV" lights are basically worthless in any residential HVAC application. They are primarily a moneymaking product for companies. That is not to say the companies don't believe in them but there is no empirical data supporting their value and many solid studies to deny their viability.

[Irascible]

Originally posted by classical
That is not to say the companies don't believe in them but there is no empirical data supporting their value and many solid studies to deny their viability.Are there any links to these studies? I read a couple way back that attempted to prove benefit. Their methodology was dubious. But I haven't seen studies clearly proving no benefit. Just a smidge of common sense combined with little understanding of basic science it all one needs to know UV lights are usually worthless. But I like seeing the studies anyway.

[kcmk]

Originally posted by milkman's daughter
Kevin,

Is you unit a heat pump? Ours is. I am wondering if this is a problem that heat pumps have more than regular units. I've heard yes and no by dealers.

Also, the filter type. I've been told the filter is good and not impeding air flow (not by the seller of the filter).

Ghads
Milkman, our system is NOT a heat pump. And coincidentally (or not), our old AC and coil were Bryants (as is the original furnace, which we are still using). The word is that Dirty Sock Syndrome (DSS) is more prevelant in heat pump systems, but can happen in regular AC systems as well (like ours).

No offense to anyone on this board...please...but my experience in this last year+ (since our DSS problem began) has been that opinions on DSS are like belly buttons...everyone has one, but they're all different. I have been told I needed to replace my coil, I did...I needed to clean my coil, I did...I needed an expensive furnace cleaning (incl. blower motor, etc.), I did...I needed an entire new furnace, I DIDN'T...I needed to monitor my house humidity, I do (39-48%)...I needed to install a condensate pan disinfectant, I did...I needed cheap filters, I needed high Merv pleated filters, I needed something in between, I needed duct cleaning, I don't need duct cleaning.....you get the idea. Through all of this, only ONE time has someone entered my home and given me advice that did not entail making a big purcha$e. Milkman, I sense you feel you are running out of options and are frustrated. So are we, but let common sense and calm prevail, or you will find yourself in my position, with a huge moneypit in the basement of your home.

I don't think anyone knows what causes DSS, nor why, nor how to resolve it. If I had it to do over again, I would start with the small inexpensive things (like cleaning my furnace blower motor myself, using a little better filter (a pleated Merv 7 should be enough), etc. Replacing entire systems, etc. should be a last resort.

[toowanbee]

For heat pumps only.

Something our company has done to help with DSS is to offer the customer something that we call "cooking the coil". When you cook something, you are killing all the organisms in the food by raising the temperature to 160 degrees. What we do is run the heatpump with a high head pressure for 5-10 minutes which brings the coil to 160 degrees. We have had much success with this method. Warning, the unit was not made to run at these pressures and could cause a leak. We warn all customers.

Something I have been thinking of lately is another method. That is to run your unit with the fan on all summer. This is when the mold growth occurs. Mold needs food (dust) and water to grow. By running the fan all the time, you dry up all that water on the coil after it has finished cooling, and in turn, do not allow the growth to occur. This causes high humidity in the house so you will need to invest in a dehumidifier. I have not proven this method yet.

By the way, the reason you smell the smell when you put on the heat and not during the summer is mold offgases when it dries. Hope this helps.

[kcmk]

MMD, the word from Trane is that they do not offer factory-coated coils. If Trane doesn't, then I would be surprised if anyone else does. I have heard of aftermarket coating solutions...Bronz-Glo, Technicoat, and others. I would suspect these solutions would not be for us, as I would think you would need to install this coating on a clean coil...not one that has already been attacked by mold, etc.

Someone mentioned setting the thermostat to "On" in the cooling season, instead of "Auto". This may help the problem some, as it would run the furnace blower motor continuously, even when the AC is not running/cooling. It would force continuous air across the coil and disipate any residual moisture more quickly...making it harder for nasties to grow there. Of course, you should not HAVE to do this, if these systems were designed/installed properly. And, it may come with some drawbacks...your electric bill will be slightly higher (as the blower is constantly running), and I assume the wear on the blower motor would be exacerbated (some may disagree, stating it's harder on the motor to be cycling on and off).

Kevin

[milkman's daughter]

We tried the fan on continuously during the summer, didn't work...

Thanks for responding Kevin, wish we could figure this out.

[genesis]

Milkman e-mail me or go to my web site I think I can help you.

[Susan P]

We have a York 3 ton unit, compressor outside air handler in the garage. It is 9 years old. We turned the heat on 2 weeks ago in Florida and noticed a funny smell coming through the ducts, not constant, but it was there. We thought it might be coming from outside, anyway I saw the fan was not turning on the compressor, so a tech came out and replaced the compressor fan motor. No smell for about a day, but it came back. Not constant, but seems to come when the outside temp is below 40. When we turn on e-heat or aux no smell at all. Can you help? We do not have mold or mildew in our house

[HVAC9900]

Hey Milkman ,frustrating situation for you.

Haven't seen the set up of your air handler room/area so need some info.

What type of drain set up is in the area of the air handler?
Is your condensate drain from the air handler piped directly into a drain pipe, or does it go to an open drain?
Or is it a condensate pump that runs the condensate somewhere else?

I assume the coil is on the supply side of the air handler fan; or is it possibly in the return side?


Do you have a condensing furnace(or any gas/oil fired),or water heater,other fuel fired appliances?

Has anyone done testing to see if you have a negative pressure in the home,especially when the air handler is running?

[Susan P]

No tests were done, The problem developed when the fan on the compressor stopped turning about 2 weeks ago. Could an electrical fault have done in the fan motor and now be causing the smell? Last night the smell came in on e heat. Could condensation from the compressor go into the coils?
The air handler is in the garage, the compressor outside. How could dirty sock syndrome develop so fast? I have to get somebody out here, Hard to find a good tech, that's why I am using the forum, so I know something. Any help would be most welcome.

[Flummoxed]

MMD, the word from Trane is that they do not offer factory-coated coils. If Trane doesn't, then I would be surprised if anyone else does.

Kevin

We have a new Lennox heatpump and new ducts and noticed DSS in the defrost cycle within the first week. Service man came out the other day and sprayed coil with a disinfectant spray and told me if that didn't work they would give us a coated coil, they say the coated coil always takes care of the problem. The spray didn't work so we're going to call them for the coated coil. Don't know if it's a factory coat or after market but Lennox offers them as the solution non the less. I'll ask the tech if what kind of coating it is.

Milkman's Daughter: on other DSS threads other people have commented that the coated coil works. Don't know when they will be replacing ours but I'll post back and let you know if it works for us.

[pmeunier]

We have a new Lennox heatpump and new ducts and noticed DSS in the defrost cycle within the first week. Service man came out the other day and sprayed coil with a disinfectant spray and told me if that didn't work they would give us a coated coil, they say the coated coil always takes care of the problem. The spray didn't work so we're going to call them for the coated coil. Don't know if it's a factory coat or after market but Lennox offers them as the solution non the less. I'll ask the tech if what kind of coating it is.

Milkman's Daughter: on other DSS threads other people have commented that the coated coil works. Don't know when they will be replacing ours but I'll post back and let you know if it works for us.

Best way is to not provide an opportunity for the mildew and fungus to grow in the first place. Even if coated it's a water reservoir and will keep everything around it moist. It's not just the coil, the mold can grow in the drip pan, etc... Keep the whole thing clean with a furnace filter MERV 8-11 and keep it dry

[Susan P]

:rolleyes:Hello to all! Updating my smelly air post. The tech came out today and yes, the coil is bad. It seems that when the compressor fan motor went out and the compressor was still running it overheated the coils and thus the smell. My unit is 9 years old, so we are thinking about replacing it. What is a great 13 seer. 3 ton unit to consider? We have electric heat pump in Florida. Thank you

[toptech]

I read this wholepost looking for the big payoff and nothing~~~~
Whatever happened to the milkman?

[genesis]

Susan I'm sorry I can't by the fact that the outdoor condenser fan motor went out, thus causing extensive mold growth on your evap coil. Dirty sock syndrome is caused my mold growth in your HVAC system from aspergillus niger mold that is common in most outdoor environments. This mold growth gets ideal conditions during the a/c season. When you switch over to the heat pump mode in late fall in your area. The heat pump has to generate enough heat to kill the existing mold growth that has developed during the summer on the evap coil.
I blame most of the problems with DSS syndrome and heat pumps on a design problem from the manufactures of the HVAC system from the factory. Gradually over the years we have seen the evap coils getting larger per ton in surface area and the evap temps creeping up too. I believe this is where the first problem is. The second problem is the reduced temp on the evap coil in the heat pump mode because of the higher SEER ratings and larger evap coils will not kill the existing mold spores on the coils.
Its almost impossible to rid your self of the odors after you get the problem for an extended period of time because the mold spores will actually move into the plenum.
You most likely need to change the evap coil just because you have DSS not because you have had a condenser motor out. After you get the new coil or system installed I would recommend that you increase your filtration to at least a Merv 12 or 13 which ever your contractor thinks it can handle. And add UVGI lighting on the return side of the evap coil. The mold and dirt does not collect on the supply side of the coil. Sanuvox or Dustfree's bio fighters are good lamps for this.

[Susan P]

:)Hello,
Can anyone tell me the good, the bad, and the ugly about Tempstar heat pumps systems. We will probably upgrade our unit, we now have York, it is almost 10 years old. We are thinking about 13 seer, 3 ton electric. I am in the dark about what make can be the best.
Thank you,
Susan and Tweety from Florida

[Susan P]

:)Hi,
Can anyone tell me what electric heat pump-ac air handlers use coatings on the coils or antimicrobial sprays?
Thank you,
Susan

[moe663]

Your condenser fan motor has nothing to do with your mold or smell in your evap coil area. Replace the evap coil, air plenum, & maybe even a few ducts at the plenum and start a new anti mold program as stated in earlier post

[Susan P]

I am looking to purchase a new air handler without toxic formaldehyde insulation. Our new tempstar made my mother and I ill from the noxious fumes coming through our ducts. heat off for now!

[dano]

As of 2007 Trane will replace coil with a teflon coated coil(Black fins). If you have the extended warranty it's all covered. If not you might have to pay labor.

[dano]

The last study on DSS from Trane states that the smell is a reaction to VOC's that exist with in the house that attach to the coil and then off gas during heat cycle.
It sure smells like mold growth to me though. And it seems to come only ever few years in my area of Florida. A good test is to cook the coil to 160 and then take a whiff, you will smell it if it's the coil. Cleaning coil with BBJ super foam & treating with BBJ C-1 Maintain does the trick on 90%. I have been advise before that you should not use a filter that is more than a MERV 8 rating? The customer usually only smells it from a few registers only and can also describe it as chemical smell or vomit if you can image that.
On one of our last DSS calls with a 10 year old Bryant unit, we cooked the coil and did not smell anything. So the Tech keep checking and found that the refrigerator was giving off a terrible musty smell . Opened the service cover and found a lot of hair in the defrost tray that smelled really bad. So he cleaned the pan and we will wait to see if complaint continues.

[mcn6]

Thought I would post my recent experience with DSS since this thread was a big help trying to figure it out. I apolagize in advance for the length of it however.
We live on the south central Oregon coast. Relative humidity averages probably in the 85-95% range throughout the year. In the summer of 2006 we had a 3 ton, split system, Amana heat pump installed. This was new construction with all new components. In the spring of 2007, for reasons unrelated to DSS, we had the original and still fairly new 12 seer Amana condensor and evaporator coil/cabinet replaced with Amana 14 seer components. Last October we began using the new 14 seer components in heat pump mode for the first time and DSS started almost immediately during defrost cycle only. The musty smell would start about 1/2 way through defrost and pretty much stink up the whole house within the remaining 5 minutes of the cycle. Several minutes later the smell was mostly gone from the supply ducts, but not the house. It was pretty bad!
The condensate pan was dry, the coils were clean, there were no signs of moisture or mold??? Why the stink? First call was to the installing HVAC contractor...AGAIN! By this time he's sounding pretty tired of dealing with me, however he does suggest a jumper between W-1 and W-2 inside my thermostat which turns on the heat strips when the condensor goes into defrost. This really helped a lot! Probably got rid of 75% or so of the stink making it at least bearable, but still not acceptable. Next I mention the coatings and treatments discussed here for the evaporator coil and the contractor states he has never heard of anything like this. This is also about when I begin noticing that my sinuses are becoming stopped up in the morning. My wife does not have this problem however and she's in the house all day???
Next is about when I think I stumbled across this thread and (only half thinking it will even work) install two 36 watt UVC lamps in the coil cabinet on the return side. Within 48hours the stink is gone even with the thermostat jumper for the heat strips removed and my sinuses are again clear in the morning. My wife claims she can still smell a very small amount of DSS every once in a while though, I do not smell anything???
Anyway, thats where it stands right now. I've got a kind of uneasy feeling about everything at this point though, like this isn't over yet or something. We'll see...
Also, I have found that UVC lamp and fixture prices vary dramatically so shop around if you decide to go that route.
Good luck.

[mikesands]

The smell is from recycled aluminum. Throw the coil away and get a new one, you just got one with too much crap in it and not enough aluminum. This has nothing to with gas heat or a heat pump.

[genesis]

The smell is from recycled aluminum. Throw the coil away and get a new one, you just got one with too much crap in it and not enough aluminum. This has nothing to with gas heat or a heat pump.

http://www.mysmiley.net/imgs/smile/confused/confused0040.gif

[mikesands]

http://www.mysmiley.net/imgs/smile/confused/confused0040.gif


That's what it is.

[mcn6]

The smell is from recycled aluminum. Throw the coil away and get a new one, you just got one with too much crap in it and not enough aluminum. This has nothing to with gas heat or a heat pump.

A lot of stuff is not making sense to me about this DSS stink thing... Like turning my coil cabinet into a tanning salon for mold... I'll add throwing my brand new coil in the trash because it contains recycled aluminum to the list.

[mikesands]

A lot of stuff is not making sense to me about this DSS stink thing... Like turning my coil cabinet into a tanning salon for mold... I'll add throwing my brand new coil in the trash because it contains recycled aluminum to the list.


Well,

If you search the net on this subject you can come up with several studies and experiments done and paid for by the people that sell these coils, usually Trane. I would be skeptical of a company that conducts or pays for an evalution and ends up with a result that happens to favor them.

Anyway, if you replace the coil with a coil that has no recycled aluminum the problem will go away forever, gaurantee it and have seen it done. This is why coating a coil works, its not that the coating is doing anything other than covering up the coil that has contaminted recycled aluminum in it.

[mikesands]

MMD, we have been having the same problems, since we replaced our old Bryant AC/coil with a new Trane in Aug '03.. Smell started Oct '04, Trane replaced coil with a second in Nov '04. It ran fine until this Oct '05. Now it's smelling again! I don't know what to do either. NO ONE seems to have an answer. We have had HVAC dealers, duct cleaners, mold remediation people, Trane reps., etc. all at our house....no one knows how it started nor how to fix it. Is your coil a Trane by any chance???

Kevin


This is what typically happens in these cases,

So what is the difference in the coil he had before and the one he has now ? It's the makeup of the metals in the coil.

[genesis]

Well,

If you search the net on this subject you can come up with several studies and experiments done and paid for by the people that sell these coils, usually Trane. I would be skeptical of a company that conducts or pays for an evalution and ends up with a result that happens to favor them.

Anyway, if you replace the coil with a coil that has no recycled aluminum the problem will go away forever, gaurantee it and have seen it done. This is why coating a coil works, its not that the coating is doing anything other than covering up the coil that has contaminted recycled aluminum in it.
Thanks I needed a good laugh.
Aluminum is a porous metal alloy mold needs something porus to adhere to. When you purchase a dipped coil you are getting a coil with a coating developed for salt water use that has a coating on it to keep the salt off of it. It just so happens to be less pourses so the mold spores wont stick to it as easy as it would an aluminum coil. Bad news is if you let this problem go untreated for a period of time it will move in to the duct work and no duct cleaning will ever cure it.

[mikesands]

Thanks I needed a good laugh.
Aluminum is a porous metal alloy mold needs something porus to adhere to. When you purchase a dipped coil you are getting a coil with a coating developed for salt water use that has a coating on it to keep the salt off of it. It just so happens to be less pourses so the mold spores wont stick to it as easy as it would an aluminum coil. Bad news is if you let this problem go untreated for a period of time it will move in to the duct work and no duct cleaning will ever cure it.



Tell me why the guy who never had the smell then has his equipment changed now has the smell ?

That is the pattern in most cases.

[genesis]

My theory is the newer higher SEER rated systems are operating the evaps at a higher temps that promote mold growth. In the old days if you were running coil temps in the 34 to 36 degrees with less surface area on the coil. The temps are low enough that you hardly ever herd of a residential system with DSS it was more common in commercial systems where the operator was keeping their space in the 65 to 68 range in humid climates.
Today's evap coils have more surface are to be more efficient in refrigeration in heat removal. And they are running close to 40 degrees that helps the mold germinate. Aspergillus niger is the most common mold spore and it is every where including in your HVAC system. It will set dormant until the ideal growing conditions occur. And a 40 plus degree coil that has water condensing on it is ideal conditions. Then to top things off in the heat mode on a heat pump we are running a lower temp, hot enough to cook it but not hot enough to deactivate it. And when you agitate mold it will release more spores and re germinate like a dandelion. Just a theory any way from the hundred or papers I read every month. You can find several papers on my FAQ page on my web site where we have been testing and developing a PCO technology to be released in March nationally with one of the big three for commercial use. I will try to put up so links to DSS on my site when I get off this job site and back to the office.

[mikesands]

Plenty of coils that ran an ADP above 40 before high SEER equipment came along, every slightly undersized or overloaded unit would have, if cold is what causes the bacteria to release then why can it grow at above 40 but then get released at above 40 at other times ?

Don't understand why the size of the coil would matter ? Many contractors B4 high SEER were of the belief that a larger coil would provide more dehumidification so there were a lot of them out there with largeer than necessary coils , which often produced a little higher suction temp and ADP , there were a lot of systems not operating in the below 40 coil temp range.

The only real difference between not having DSS times and having it now is the cheap aluminum that coil manufacturers are using, don't know how you can dismiss that idea without looking into it.

[mcn6]

I am not disputing the recycled material theory, I wouldn't know it's validity one way or the other... Since the stink is still gone after almost three weeks... More just dismissing the idea of trashing my evap coil anytime soon.
What impurity's do you figure remain in the aluminum after the recycling process that would cause the stink?
Any thoughts on why powering the heat strips during defrost would be so effective?
Also, any thoughts on why there is no smell in the summer from the A/C? Basically the same thing is happening during the defrost cycle... No?
And last, how exactly would someone go about "cooking the coils" mentioned earlier in this thread?
Not trying to cause heartburn for anybody... Just a couple things still not making much sense to me???
Anybody?
Thanks

[mikesands]

Well my theory is that it is bacteria that causes it and the bacteria grows during a heating cycle. and then is released during a cooling cycle. So given a good home to breed the bacteria runs this cycle.

That would be why during the summer you don't see it unless you're AC has been off for some time and the bacteria had a chance to grow on a warm coil. Then it offcoiled when you turned the AC on and the coil got cold, same thing during heatpump defrost. Bacteria grows during normal operation and offcoils when the coil gets cold.

My difference is that the cheap-recycled-low grade-aluminum coil holds more of the bacteria to begin with because it isn't 100% aluminum and it is more conducive to trapping the bacteria on it. I'm not a chemical engineer I'm just looking at it logically and I haven't heard a more logical explanation yet, none of the theories out on the web or in this thread have meat on their bone, all of them can easily be shot down. Except mine,

[jatibb]

new here, been following this. we have a new unit, replaced july 08. ac all summer good, after first few weeks of cold, dss. not always, not when emergency heat used, but 1- 2 times a day. am going to clean coils,pan,drain,filter... big question is ,what is this mold and is it harmfull? name with niger in it makes me think black mold?

[mikesands]

new here, been following this. we have a new unit, replaced july 08. ac all summer good, after first few weeks of cold, dss. not always, not when emergency heat used, but 1- 2 times a day. am going to clean coils,pan,drain,filter... big question is ,what is this mold and is it harmfull? name with niger in it makes me think black mold?

Well yur one for one, one post and one report abuse.

[mcn6]

Well yur one for one, one post and one report abuse.

Thank you for your input. It will be interesting to me when this is all figured out. Just way too many loose ends for me to feel confortable that I have seen/smelled the last of it...
On the quote above: I believe the reference was to niger asparillius (sp) or whatever. It does not appear to me that the poster was thinking what your thinking he/she was thinking. I think.:mad:

[mikesands]

Thank you for your input. It will be interesting to me when this is all figured out. Just way too many loose ends for me to feel confortable that I have seen/smelled the last of it...
On the quote above: I believe the reference was to niger asparillius (sp) or whatever. It does not appear to me that the poster was thinking what your thinking he/she was thinking. I think.:mad:

Actually , it was pretty clear what he meant by it.

[jatibb]

nice, i guess if i order a burrito with frijoles negroes im being racist also, jesus
black means black. i guess no answer from you then?

[mikesands]

new here, been following this. we have a new unit, replaced july 08. ac all summer good, after first few weeks of cold, dss. not always, not when emergency heat used, but 1- 2 times a day. am going to clean coils,pan,drain,filter... big question is ,what is this mold and is it harmfull? name with niger in it makes me think black mold?

Ok give you the benefit of the doubt.

The big answer to your big question can be answered by looking up Aspergillus Niger, yes , its black mold. So you probably have A. Niger lurking around in your home , how does that make you feel ?

[genesis]

Jattibb you need to get you mind out of the gutter an use google a bit more appropriately. Stachybotrys is the notorious black mold.
Stachybotrys
From Wikipedia, the free encyclopedia

Stachybotrys

Scientific classification
Kingdom: Fungi

Phylum: Ascomycota

Class: Sordariomycetes

Order: Hypocreales

Family: Dematiaceae

Genus: Stachybotrys


Species
S. chartarum
S. cylindrospora


Stachybotrys is a genus of molds, or asexually-reproducing, filamentous fungi. Closely related to the genus Memnoniella,[1][2] most Stachybotrys species inhabit materials rich in cellulose.

The most infamous species, S. chartarum (also known as S. atra) is known as "black mold" or "toxic black mold," and is frequently associated with poor indoor air quality that arises after fungal growth on water-damaged building materials.[3] It is known to produce trichothecene mycotoxins including satratoxins.

[jatibb]

nice to know you cany say the word niger, about anything, w/o someone playing the race card. that is NOT what i meant! simple question requiring a simple answer, thats all. why google when im here with what i thought to be knowledgable people at the time. guess ill google touchy-feelly before asking anymore questions ..concerning anything

[mcn6]

The consensus here seems to be a mold or bacteria causing DSS. I have not read anything conclusive as to what type of mold/bacteria it is or if it even is m/b or wether it is a single, specific m/b??? Could be different m/b in different parts of the country??? I do know that after 1 1/2 months it appears that I may have developed an allergic reaction to whatever it is. I say "may have" since I am not 100% about that either???
Apparently, at least in my case, defrost cycle is creating ideal temperature and moisture conditions in and around the evap coil for DSS to occur??? Using cooling mode does not seem to cause DSS even though similar conditions are present??? Usually with a unit operating in "emergency" mode (heat strips only) the compressor is not running, nothing is changing at the evap coil = no DSS??? In my case, powering the heat strips with the compressor running (defrost cycle only), seemed to reduce the stink considerably, possibly killing or burning off whatever as it passed the strips???
Exposing the evap coils to UVC light has worked for me so far. Others report it has not worked for them??? From what I have read, the coil must be exposed to sufficient UVC intensity and/or dwell for UVC to be effective.
Anyway, that is most of what I don't know about DSS... LOL!


new here, been following this. we have a new unit, replaced july 08. ac all summer good, after first few weeks of cold, dss. not always, not when emergency heat used, but 1- 2 times a day. am going to clean coils,pan,drain,filter... big question is ,what is this mold and is it harmfull? name with niger in it makes me think black mold?

[jatibb]

THANKS, still looking into a uv light. on another note though, are the materials inside of a air handler built or capable of withstanding uv light all the time w/o breaking down? the sun can have pretty disasterous effects on some plastics,rubber parts etc..

[mcn6]

That is a concern I have w/uv light also. From what I have read, almost all plastics will deteriorate to some degree when exposed to UV light, some faster and more severe than others. For the most part the only plastic I have in the coil cabinet is the drain pan liner. I intend to monitor that as I replace UVC lamps. At any rate I figured it was worth the risk + UVC has several other benefits in this application.
I reasoned it out this way: My new house stunk pretty bad and I suspected I was reacting physically to whatever was causing the stink. I figured I didn't have much to loose by trying the UVC treatment at that point. Hopefully someone will come up with what exactly is going on with DSS. I will deal with it again at that time. For now I can at least enjoy in my new house. I have notified my installing contractor of the problem and intend to contact the manufacturer in the near future.

[jatibb]

possible silly and/or dumb question, if this mold grows on the coils is there anyway to kill it? the chemical listed earlier, is it a cleaner or does it just mask the odor of said mold? would it be possible to use a propane torch to heat the coils or would that damage coils and?or mold grow back anyway?

[August59]

Well my turn I quess and hope we can come up with something. I'll run down my equipment and chnages to it over last few years (not much).
Built my house in 1993 and had a Tempstar 9 SEER Gas Pack (?) installed and it ran good for 11 years with no odors or problems. When it broke the day before Christmas my problem ended up being a cracked heat exchanger. I opted for a new unit as a friend of mine was then working with an HVAC contractor and gave me what I felt was a good deal. Back to my old unit and as I mentioned it never gave me any problems up until that day. My only "CON" about the system was that when the fan came on you had to turn up the TV because it sounded like a jet engine starting up.
New unit installed around Christmas, 13 SEER Amana GAS Pack with a stainless steel heat exchanger with lifetime warranty. Things went well until spring comes and we switched to a/c for first time and whew what a smell (dirty socks, vomit, or whatever it is) which lasted about 6 hours before it cleared the house. A week or so with no problems and it turned called and on come the heat and here comes the stinch from h@##, back to air couple of days later and same thing for about 6 hours or so and nothing for the entire rest of the summer unti the first day to use the heat. Gag time again for about 6 hours or so and that is the way it has been for 3 years. Contractor has came out and cleaned coils a couple of time, but know good and they pretty much threw up there hands and said it wasn't there unit causing it. My reply was, The problem did not start till you put your product in and the problem is still there because you put your product in. So fix it or take it out and I' found another one. Waiting to hear back from them but they don't have a clue.
My biggest question is - Why does it do it with new unit and not the old unit? Stainless steel heat exchanger? Slower (or quiter fan)? Air at register seems to be a little hotter with new unit as with older unit? Any thoughts!!!???? Thanks ahead of time
P.S. There was know ductwork done when the units were changed out.

[jnixon550]

A uv light light or a good anti bacterial coating on your heat exchanger should do the trick. Otherwise you might need to have your ducts cleaned. That could be part of the problem. the mold could be living in your ducts and when you turn switch your unit the mold molecules get agitated and blown around again. But I would try the uv lights or the coating first as that is most likely the problem

[August59]

I guess the thing that puzzles me the most is that the old unit worked fine for so many years and as soon as new unit is installed "presto" we have a horrible odor for the last 5 years everytime we switch from heat to air or switch from air to heat. Through the middle of summer or middle of winter there is no problem. Thanks

[cb975]

First i want to say the theory about recycled aluminum being the cause is nonsense. Aluminum, whether recycled or virgin, is used on hvac evap coils due to it heat transfer abilities and it's ability to shed water without beads forming. this is neccesary to reduce backpressure of the airflow across the coil and to ensure more condensate makes it to the drain rather than being blown back into the supply duct. Becuase of this key aspect of aluminums role one would logically assume that regardless of whether the aluminum was recycled or virgin the equipment manufacturers would use and alloy with specific surface properties to serve that purpose, meaning there would be no difference in the end product simply because the original raw material was procured from a different source.

Next i would add that current system designs do contribute to the intensity of the DSS but are not by any means the source. Over the past decades as efficiency minimums have increased coils have gotten not only larger but the aluminum fins have become more tightly packed together creating smaller crevasses ideal for harboring contaminants. In addition, when once systems were designed for 400 cfm per ton airflow now most are designed for 350 cfm per ton to achieve efficiency and this allows for a lower airflow velocity through the coil which could potentially make it easier for airborn contaminants to land on the coil and stick. While these may seem like smoking gun details i would remind everyone that they are neccessary to meet ARI standards and are by no means the source of the underlying issue.

Before commenting on the issue at hand, DSS, i want to state that dirty sock syndrome can result from any source of bacteria, mold or fungus whether it is be a new pet, leaking ducts, spores picked up on a weekend hike, an improperly installed drain line or a different strain of athleets foot picked up at the gym. It simply results from the culmanation of various circumstances that lead to contamination of the evap coil. That being said, it's impossible to say there is a 100% effective way to rid your home of DSS, there are only ways to treat and hopefully prevent first of which is annual cleaning (reccomended by most manufacturers any way).

If a cleaning is done, whatever chemical is used the cleaning must be thorough and the chemical remain in contact with the coil long enough to ensure a positive effect. UV Lights?...only treat surfaces within a few inches of the light so are useless for the inner surfaces of a coil. Good filtration?...excellent preventative measure but not always viable because better filters must be larger or they could restrict airflow reducing system capacity and result in premature failure of a compressor.

It's true that coils coated with a antimicrobial compound are extremely effective but any treatment will loose it's effectiveness with time so even a treated coil is not a permanent solution.

There is no one answer here so do your homework and check facts not just forums.

Good luck

[genesis]

First i want to say the theory about recycled aluminum being the cause is nonsense. Aluminum, whether recycled or virgin, is used on hvac evap coils due to it heat transfer abilities and it's ability to shed water without beads forming. this is neccesary to reduce backpressure of the airflow across the coil and to ensure more condensate makes it to the drain rather than being blown back into the supply duct. Becuase of this key aspect of aluminums role one would logically assume that regardless of whether the aluminum was recycled or virgin the equipment manufacturers would use and alloy with specific surface properties to serve that purpose, meaning there would be no difference in the end product simply because the original raw material was procured from a different source.

Next i would add that current system designs do contribute to the intensity of the DSS but are not by any means the source. Over the past decades as efficiency minimums have increased coils have gotten not only larger but the aluminum fins have become more tightly packed together creating smaller crevasses ideal for harboring contaminants. In addition, when once systems were designed for 400 cfm per ton airflow now most are designed for 350 cfm per ton to achieve efficiency and this allows for a lower airflow velocity through the coil which could potentially make it easier for airborn contaminants to land on the coil and stick. While these may seem like smoking gun details i would remind everyone that they are neccessary to meet ARI standards and are by no means the source of the underlying issue.

Before commenting on the issue at hand, DSS, i want to state that dirty sock syndrome can result from any source of bacteria, mold or fungus whether it is be a new pet, leaking ducts, spores picked up on a weekend hike, an improperly installed drain line or a different strain of athleets foot picked up at the gym. It simply results from the culmanation of various circumstances that lead to contamination of the evap coil. That being said, it's impossible to say there is a 100% effective way to rid your home of DSS, there are only ways to treat and hopefully prevent first of which is annual cleaning (reccomended by most manufacturers any way).

If a cleaning is done, whatever chemical is used the cleaning must be thorough and the chemical remain in contact with the coil long enough to ensure a positive effect. UV Lights?...only treat surfaces within a few inches of the light so are useless for the inner surfaces of a coil. Good filtration?...excellent preventative measure but not always viable because better filters must be larger or they could restrict airflow reducing system capacity and result in premature failure of a compressor.

It's true that coils coated with a antimicrobial compound are extremely effective but any treatment will loose it's effectiveness with time so even a treated coil is not a permanent solution.

There is no one answer here so do your homework and check facts not just forums.

Good luck

Nice Post what is your back ground?

[cb975]

I've been in HVAC distribution and support for 11 years now. For the past 5 i have worked in a tech support role assisting contractors with various issues in the feild as well as acting as a go between from the contractors we serve to the engineers who design the equipment well sell and support. For the particular brand i support DSS has never been considered an issue with the equipment but they have been accomodating when we make efforts to help our contractors out of a tight spot when they have a DSS problem. Over the years we have encountered the issue several times and had dealers that would change coils and even switch from one brand to another changing the entire system. Sometimes they are lucky enough that the source of the DSS was taken care of in the process but most times it was not. I hope that the small amount of information i provided will be helpfull.

[snacktray]

I, too have this DSS problem, and I have a new Trane heat pump that was installed in June of 2009. I first noticed the problem on a mild summer day when I switched the fan from "auto" to "circ" to have the cool air circulated while sleeping. When the AC came on later that morning, I noticed an awful stench in the house. At first I thought it was my dog who had just been outside, but it wasn't her. The smell was very pungent and smelled like a wet dog that had been left to dry outside in the hot sun.

I noticed the smell coming from the registers in the house. I quickly turned the system off thinking something had burned up, maybe a motor or something in the AHU. I went in the attic and the smell wasn't up there, so I resumed cooling. After about an hour and a half the smell stopped coming from the registers, but it still lingered in the house and on my clothes.

Since then I have not turned the fan to "on" or "circ" in the summertime and the smell had not come back.

Fastforward to the fall.

When we had our first cool nights here in TN, i switched the tstat to "auto" and left the fan on "auto" as well. When the heatpump first came on to heat the house, the smell was back. I do not know if the aux heat strips came on to defrost because I was asleep and didn't think to look, but the smell was enough to wake me and the wife up.

Now that we are in heating season, I leave the tstat on "heat" and the smell does not show up. Now if I know the temps will get warm, I will switch the stat to "auto" before I leave just to have a cool house when I get home from work. And when I get home from work I can tell the AC has come on simply by smelling the air first thing when I walk through the door.

I have been doing a lot of reading about this and the consensus is that mold/bacteria is the culprit. I am going to have my season PM done soon and pick the tech's brain a bit to see what he thinks.

If we are able to come up with a solution, I will be sure to post here.

Thanks.

[cfg]

It appears we have also been hit with the DSS issue on our two brand new heat pump systems. We have a hybrid system on the first floor. I tried to run the gas furnace for a day or two (forcing the TH to emergency heat) -> no luck.

Our HVAC contractor started to call Amana -> their initial standard reply was to use a cleaning solution or using a UV light.

Does anyone has any experience dealing with Amana and getting new coated coils under warranty?

Thanks in advance for any suggestion.

[TalkingHead]

A word of caution: If you end up with a coated coil don't also put in a UV light that radiates the coil. The UV can deteriorate some coatings releasing harmful gases. If you put a UV light anywhere else in your system make sure it doesn't shine on flex duct. Plastic and UV lights don’t play well together.

[AirBoy4u]

I have heard that the RGF Guardian air purifier will kill the DDS odor. www.rgf.com

[cfg]

A word of caution: If you end up with a coated coil don't also put in a UV light that radiates the coil. The UV can deteriorate some coatings releasing harmful gases. If you put a UV light anywhere else in your system make sure it doesn't shine on flex duct. Plastic and UV lights don’t play well together.

Thanks a lot for the information. My question is if someone knows what kind of coating is used by Trane / Amana.... to address the issue.

I know the coating used to protect the coil strips from corrosion seems to be the standard. But then I have read about athalene II / REP-60 / agION .....

Thanks - Didier.

[cfg]

I have heard that the RGF Guardian air purifier will kill the DDS odor. www.rgf.com

Thanks for the recommendation. I am trying to determine if this unit produces Ozone?

[beachtech]

A uv light light or a good anti bacterial coating on your heat exchanger should do the trick. Otherwise you might need to have your ducts cleaned. That could be part of the problem. the mold could be living in your ducts and when you turn switch your unit the mold molecules get agitated and blown around again. But I would try the uv lights or the coating first as that is most likely the problem

this cracks me up everytime i read it ROFLMAO

[beachtech]

aluminum is a very porous metal as well.

do a google serch for "how porous is aluminum metal" and you will find a lot of stuides, research and technics that have been done and found to help prevent and keep this metal from being so porous. But it is still an issue when you're talking about microscopic sized bacteria and places for it to attach to and bond with.

expecially mold. porous is the reason why drywall is so difficult and nearly impossible to "clean" after mold spores have started.

only one way to kill those bacteria, and that's to eliminate the food source of moisture. and that's not going to happen in an air conditioning coil.

during the seasons of in between heating and cooling and during defrost cycles in the winter, the moisture is re-entroduced to the bacteria in the porous metal and the funk begins to pour into your living space.

and we have had great success with UV lights. and as far as just the surface? can you explain why some systems we have had to replace non UV resistant drain pans, because the pans had lines ate in them from where the light shined though the coil???

[victor61]

I had a new Heat Pump installed in April of this year. I have the classic DSS symptoms--when the unit goes into defrost.

The dealer has no interest in this problem, saying it's due to environmental conditions. Well, hey, when you have a petri dish for an evaporator coil, any number of ordinary microbes could land there and set up house.

After researching UV lights, coated coils and the like, I am probably going to take the drastic step of having a LP furnace installed and the current air handler ripped out. My wife and son have allergies, and this is unacceptable. You can't imagine how distressing it is for me to hear my son coughing and sneezing and asking for his inhaler morning after morning. I live in eastern Pennsylvania, and this phenomenon was rare but is occurring more and more.

The original system cost 4500 to have installed. The LP replacement will cost about the same. There goes the summer vacation.

What a nightmare!

I have a degree in HVAC technology, and I was a tech rep for Snyder General for a time. This sort of thing didn't happen when heat pumps weren't so efficient--and had higher coil temps and fewer fins/inch on the evaporator coils. As for the recycled aluminum, I have no idea. It sounds plausible, but I've only heard anecdotal stories about it.

I would think moving to a standard furnace would eliminate this problem, since the coil would be out, and the new a/c coil would be downstream of the heat exchanger and thus see much higher temps in the winter. I'm not sure how the crud could migrate to the supply ductwork, given that there's no moisture there to sustain it.

I'm getting bids for a new furnace soon. I may then initiate a civil action against the contractor, but I don't see myself standing much of a chance, since this is a very grey area of HVAC responsibility.

Wish me luck.

[bullmoose]

I had a new Heat Pump installed in April of this year. I have the classic DSS symptoms--when the unit goes into defrost.

The dealer has no interest in this problem, saying it's due to environmental conditions. Well, hey, when you have a petri dish for an evaporator coil, any number of ordinary microbes could land there and set up house.

After researching UV lights, coated coils and the like, I am probably going to take the drastic step of having a LP furnace installed and the current air handler ripped out. My wife and son have allergies, and this is unacceptable. You can't imagine how distressing it is for me to hear my son coughing and sneezing and asking for his inhaler morning after morning. I live in eastern Pennsylvania, and this phenomenon was rare but is occurring more and more.

The original system cost 4500 to have installed. The LP replacement will cost about the same. There goes the summer vacation.

What a nightmare!

I have a degree in HVAC technology, and I was a tech rep for Snyder General for a time. This sort of thing didn't happen when heat pumps weren't so efficient--and had higher coil temps and fewer fins/inch on the evaporator coils. As for the recycled aluminum, I have no idea. It sounds plausible, but I've only heard anecdotal stories about it.

I would think moving to a standard furnace would eliminate this problem, since the coil would be out, and the new a/c coil would be downstream of the heat exchanger and thus see much higher temps in the winter. I'm not sure how the crud could migrate to the supply ductwork, given that there's no moisture there to sustain it.

I'm getting bids for a new furnace soon. I may then initiate a civil action against the contractor, but I don't see myself standing much of a chance, since this is a very grey area of HVAC responsibility.

Wish me luck.

For the amount of money you are going to spend to rip out your system and put in a furnace, you should have your indoor air quality evaluated by a reputable company. Have an air cleaner, ultraviolet light and a pan treatment installed.

With the amount of bacteria, gases and dust mites that are in the air it couldn't hurt. Not to mention the amount of skin that you and your family shed. Did you know that a 1,500 sf house produces 40 lbs of dust per year? Did you know that 42,000 dust mites live in 1 ounce of dust? Did you also know that 1 dust mite produces 20 fecal pellets a day? What happens when bacterias and mites die? Is it fair to say that they would cause an odor?

What type of air filter are you using? Sounds like you have a failure of your filter... When I say get a air cleaner I mean a cleaner.. Not a media, not a spaceguard or air bear or anything like that. Did you know that dust particles 5 microns and below enters your lungs and can pass into your bloodstream?

Just thought I would put my 2 cents in. Maybe your contractor didn't properly explain all of this to you. But in my opinion, either way I don't think a lawsuit against them is acceptable. Good luck to you.

[victor61]

The dust and other things you mentioned do not explain, to me, the DSS. That started with installation of the new unit. I use an allergy filter. But filters would catch the particulate matter before it gets to the coil, or most of it. The problem is that the coil is now running perfect temperatures to incubate microorganisms. The byproducts of these microbes metabolic processes are released all at once in the defrost cycle when the coil becomes damp.

Installing a filter would clean the air before it reaches this area, but would do nothing to address the breeding ground. It's a bit like killing Terrorists in Afghanistan when they just keep making more in Pakistan, to use a political metaphor. And, the microbes are being created after the filter, so it would only catch some of them each time, and not really get to the source.

As for the contractor, they should at least provide due diligence by working with me on a solution, even if I absorb the cost.

Yeah, the LP furnace is a radical solution. I may have an indoor air quality company do some testing, but I don't know a thing about how accurate these things are. Like so many HVAC solutions/diagnoses, there are a lot of claims that are debatable. UV lights are praised by those who manufacture them and subsequently derided as ineffective by another manufacturer of the same product! Even the vaunted HEPA filter has come under fire in some studies.

The consumer is left to wade through claim and counter claim, and myriad theories. There are so many stories of people spending money on UV lights, coil cleanings, filters....only to find the problem remained.

My best guess right now is that the SOURCE of the problem is that coil. The coil must be cleaned, remain clean or be removed. Its likely that there is some aspect of my house that predispose the coil to contamination, but finding that source is a needle in a haystack. Do I start cutting into drywall on hunches? Where does it stop? Again, I think it stops with the coil, which is the variable that changed. The household environment has not--no water penetration, nothing.

The HVAC industry has been negligent, in my opinion, in addressing this issue of DSS. There are things they could do to these coils, but as long as consumers accept the situation, and there is no financial repercussions for the dealers, distributors, or manufacturers, they have no incentive to change. After all, DSS affects only about 2% of units.

Litigating something like this is costly, certainly more than the average consumer has to spend. It would involve subject matter experts, and counter claims about the cause of this troubling phenomenon.

But, we KNOW it happens to high efficiency heat pumps in defrost mode. Most of these cases are associated with the installation of high efficiency units. Again, THAT is the variable that changed.

But I go on.

I will probably consult an environmental company to test the air in my house. There is a time issue, as my son has chronic asthma.

[genesis]

The dust and other things you mentioned do not explain, to me, the DSS. That started with installation of the new unit. I use an allergy filter. But filters would catch the particulate matter before it gets to the coil, or most of it. The problem is that the coil is now running perfect temperatures to incubate microorganisms. The byproducts of these microbes metabolic processes are released all at once in the defrost cycle when the coil becomes damp.

Installing a filter would clean the air before it reaches this area, but would do nothing to address the breeding ground. It's a bit like killing Terrorists in Afghanistan when they just keep making more in Pakistan, to use a political metaphor. And, the microbes are being created after the filter, so it would only catch some of them each time, and not really get to the source.

As for the contractor, they should at least provide due diligence by working with me on a solution, even if I absorb the cost.

Yeah, the LP furnace is a radical solution. I may have an indoor air quality company do some testing, but I don't know a thing about how accurate these things are. Like so many HVAC solutions/diagnoses, there are a lot of claims that are debatable. UV lights are praised by those who manufacture them and subsequently derided as ineffective by another manufacturer of the same product! Even the vaunted HEPA filter has come under fire in some studies.

The consumer is left to wade through claim and counter claim, and myriad theories. There are so many stories of people spending money on UV lights, coil cleanings, filters....only to find the problem remained.

My best guess right now is that the SOURCE of the problem is that coil. The coil must be cleaned, remain clean or be removed. Its likely that there is some aspect of my house that predispose the coil to contamination, but finding that source is a needle in a haystack. Do I start cutting into drywall on hunches? Where does it stop? Again, I think it stops with the coil, which is the variable that changed. The household environment has not--no water penetration, nothing.

The HVAC industry has been negligent, in my opinion, in addressing this issue of DSS. There are things they could do to these coils, but as long as consumers accept the situation, and there is no financial repercussions for the dealers, distributors, or manufacturers, they have no incentive to change. After all, DSS affects only about 2% of units.

Litigating something like this is costly, certainly more than the average consumer has to spend. It would involve subject matter experts, and counter claims about the cause of this troubling phenomenon.

But, we KNOW it happens to high efficiency heat pumps in defrost mode. Most of these cases are associated with the installation of high efficiency units. Again, THAT is the variable that changed.

But I go on.

I will probably consult an environmental company to test the air in my house. There is a time issue, as my son has chronic asthma.

Victor you are actually dead on with your rational. The bacterial growth is promoted by the temp of the evap coil in the heating mode. UVGI lighting will only slow it down because the lighting does cover 100% of the coil (like the u tubes on the end and such) I have a buddy that has worked in a R & D lab for one of the big 3 and has actually reproduced the bacterial growth on a heat pump in a lab, and has verified this phenomena. If the UVGI lighting is installed during the initial installation correctly you most likely wont have an event but there is no guaranty of this fact. It takes about 1800 mw3 to break down the biologics on a coil correctly and that's a lamp every 6 to 8 inches covering the surface area. The theory of the poures on the aluminum fins has merit and probably increases the amount of particulate present on the coil to allow the more bacteria to grow. But it doesn't initiate the growth.
I was testing a hockey locker room in Minnesota 2 days ago with basically the same issue in the hockey pads. I dropped the TVOCs in the room from 9.5index points to 0 in about 2 hours figuring 8 air changes an hour through one of our portable PCO units. We maintained the 0 reading for about 12 hours till we turned the equipment off and the readings started going right back up after we turned the equipment off. DSS has the same issues , no matter what you do to reduce the odors as long as the source is still present the odors will return.

[victor61]

I'm leaning toward the radical option of having the system replaced with an LP furnace (no gas in our area). I would, at the same time, have the ducts cleaned and a good filter installed. I think they could salvage the existing oudoor unit and run it as straight a/c (with a new coil!!!!!!!!!!!).

It's a huge expense, given that I just laid out $5,000 for this system in April of this year. I'm reluctant to put money toward anything that doesn't address the core issue, which is a coil that is a perfect breeding ground for micro-organisms.

The issue of why my coil got 'infected' is more complex. Maybe it is the steam from a shower too close to the return? Maybe it's an unknown water penetration?

I don't know how much moisture is required for these odor-producing organisms to live. I hope and pray the supply ducts aren't 'infected'.

I wouldn't think the organisms could live in a dry environment. It seems they establish when there's moisture and temperature conditions that favor them.

Victor you are actually dead on with your rational. The bacterial growth is promoted by the temp of the evap coil in the heating mode. UVGI lighting will only slow it down because the lighting does cover 100% of the coil (like the u tubes on the end and such) I have a buddy that has worked in a R & D lab for one of the big 3 and has actually reproduced the bacterial growth on a heat pump in a lab, and has verified this phenomena. If the UVGI lighting is installed during the initial installation correctly you most likely wont have an event but there is no guaranty of this fact. It takes about 1800 mw3 to break down the biologics on a coil correctly and that's a lamp every 6 to 8 inches covering the surface area. The theory of the poures on the aluminum fins has merit and probably increases the amount of particulate present on the coil to allow the more bacteria to grow. But it doesn't initiate the growth.
I was testing a hockey locker room in Minnesota 2 days ago with basically the same issue in the hockey pads. I dropped the TVOCs in the room from 9.5index points to 0 in about 2 hours figuring 8 air changes an hour through one of our portable PCO units. We maintained the 0 reading for about 12 hours till we turned the equipment off and the readings started going right back up after we turned the equipment off. DSS has the same issues , no matter what you do to reduce the odors as long as the source is still present the odors will return.

[TalkingHead]

I have heard it said that the little buggers that live on your coil depend on a certain food source that is in the air and specific to your home and coil temperature. It can be hair spray, VOCs off of cleaning supplies, cooking oil, pet dander, etc. The fungi/bacteria themselves can also be specific to your home. They may not live on the coil in the home next door with the same size and model air conditioning unit that you have because that home has a different mix of food in the air. The coil temperature can even be a few degrees different between the two units due to the variations in duct work static pressure (air flow) and refrigerant charge.

[fisher01]

I've been living with the DSS for many years now and have done a ton of research on this subject. The one comment I read over and over again, old unit had no DSS, new install does. Thats what exactly happened to me. Old unit had no DSS for 15 years, new unit develops DSS in first heating season and have had it ever since. I believe the DSS is due to the use of these high efficiency type coils whereby the fins are packed tightly together causing an idea area for microbes to grow. From my DSS onset, my coil had always appeared shiny and clean, yet I have DSS in the defrost cycle which is so bad, it'll wake you from a deep sleep. Well its time for me to start my monthly winter coil cleaning, takes me about 4 hours to throughly spray and rinse the coil. Lasts about a month and then I repeat, at least by doing this the smell is tolerable. My unit is a Rheem which came with a 10 year parts/labor warranty. Rheem and its warranty has provided no help in addressing this issue, unlike some of the other manufacturers which are providing/installing coated coils to solve the problem. From everything I've read, coated coils are the solution. I have not heard from anyone with the installation of a coated coil have DSS return to their system.

[victor61]

This is exactly my conclusion. There is a direct correllation between the increase of high-efficiency heat pumps and this phenomenon. The best solution is a coated coil, if you must have a heat pump. I have heard that these coated coils tend to leak over time, but I have no data on that.

In my case, the absolute solution is removal of the heat pump and installation of an LP furnace with a/c-only coil.

This is a serious issue, since there is an energy advantage to high efficiency heat pumps that is in jeopardy if the trend is to not get one due to this particular reason.

I'm now waiting to hear from the Dealer who is in conversation with the tech rep at York. I do not anticipate them offering any viable solution, and will likely have to eat the cost of throwing out a perfectly functional heat pump that was installed six months ago, so that I can have clean air via a standard gas furnace. What a step back for energy efficiency!

The whole thing stinks (p.u.n. intended).

[TalkingHead]

This is an open question. Has anyone heard of DSS with a dual fuel system?

What would happen if you only added the LP heater and kept the heat pump? You could set the heater to come on when the outdoor temperature goes below 45 degrees. That will change the reverse cycle frequency and raise the return temperature across the coil. This may alter the life cycle of the bacteria enough to improve the condition.

[victor61]

I thought about that. It sounds interesting, and it seems like the heat from the gas would kill any bacteria on the coil, given that it would see much higher temperatures, being downstream of the hot air.

I'm still waiting to hear back from the dealer, who says he is in contact with both York and the coil manufacturer (Aspen). Interestingly, I called Aspen and got someone who was completely clueless, but was supposed to be a technical support guy. All he could tell me was, "The coil is made of metal, and copper and 'whatnot'. I ain't never heard of that problem being solved."

Nice reply, and good to know the manufacturer has such skilled people waiting to help!---NOT


This is an open question. Has anyone heard of DSS with a dual fuel system?

What would happen if you only added the LP heater and kept the heat pump? You could set the heater to come on when the outdoor temperature goes below 45 degrees. That will change the reverse cycle frequency and raise the return temperature across the coil. This may alter the life cycle of the bacteria enough to improve the condition.

[teddy bear]

I have the problem with a dual fuel heat pump install. Any time you have a spot that stays wet between heating cycles or cooling cycles, you have the potiential for odor producing bacteria to maintain the odor producing colonies. Low spots in the drain pane or wet spots under the coil feet can provide the slow drying spot. Not all bacteria produce odors. A non odor producing bacteria may dominate the wet spots-thus not all wet spots smell the same. I have had the wet sock odor grow in a plastic pail of drain water from a humidifier. There was enough nuterients in the overflow water to produce slime and odor in the pail in about 3 weeks. Having an extended dry time everyday is important to control any bacterial growth.
The only way I could control the odor was to eliminate wet spots in the pan/coil legs and operate the blower continuously. I also keep the home <50%RH during the spring/fall/summer cooling season. Regards TB

[beachtech]

I had a new Heat Pump installed in April of this year. I have the classic DSS symptoms--when the unit goes into defrost.

The dealer has no interest in this problem, saying it's due to environmental conditions. Well, hey, when you have a petri dish for an evaporator coil, any number of ordinary microbes could land there and set up house.

After researching UV lights, coated coils and the like, I am probably going to take the drastic step of having a LP furnace installed and the current air handler ripped out. My wife and son have allergies, and this is unacceptable. You can't imagine how distressing it is for me to hear my son coughing and sneezing and asking for his inhaler morning after morning. I live in eastern Pennsylvania, and this phenomenon was rare but is occurring more and more.

The original system cost 4500 to have installed. The LP replacement will cost about the same. There goes the summer vacation.

What a nightmare!

I have a degree in HVAC technology, and I was a tech rep for Snyder General for a time. This sort of thing didn't happen when heat pumps weren't so efficient--and had higher coil temps and fewer fins/inch on the evaporator coils. As for the recycled aluminum, I have no idea. It sounds plausible, but I've only heard anecdotal stories about it.

I would think moving to a standard furnace would eliminate this problem, since the coil would be out, and the new a/c coil would be downstream of the heat exchanger and thus see much higher temps in the winter. I'm not sure how the crud could migrate to the supply ductwork, given that there's no moisture there to sustain it.

I'm getting bids for a new furnace soon. I may then initiate a civil action against the contractor, but I don't see myself standing much of a chance, since this is a very grey area of HVAC responsibility.

Wish me luck.

and installing the gas furnace with an air conditioning coil, isn't going to rid you of the problem

lmao

cutting your nose off to spite your face, isn't a very logical way of thinking, but to each his own :)

P.S. no pricing in the forums :)

[beachtech]

This is an open question. Has anyone heard of DSS with a dual fuel system?

What would happen if you only added the LP heater and kept the heat pump? You could set the heater to come on when the outdoor temperature goes below 45 degrees. That will change the reverse cycle frequency and raise the return temperature across the coil. This may alter the life cycle of the bacteria enough to improve the condition.

yes, DSS happens with dual fuel systems. you still have a heat pump that runs defrost cycle and will and can allow for the indoor coil to get damn during the defrost cycle.

but doesn't happen as often as a heat pump with electric strip heaters, due to the fact that the coil is after the heat exchanger in a dual fuel split system. but is more prevelant on dual fuel packaged units where the coil is before the heat exchanger. has everything to do with coil temp and dew point at where the coil will have moisture on it during defrost cycle :)

whether the coil reaches the point where it has moisture on it or not, doesn't mean the bacteria is not there. just because you cannot smell it anymore, doesn't mean the problem is solved. hear no evil see no evil, does not mean evil doesn't exist.

DSS is nothing new. in humid climates, there are contractors that can go back 30yrs over many different types of equipment and a wide range of manufacturers :)

[beachtech]

I thought about that. It sounds interesting, and it seems like the heat from the gas would kill any bacteria on the coil, given that it would see much higher temperatures, being downstream of the hot air.

I'm still waiting to hear back from the dealer, who says he is in contact with both York and the coil manufacturer (Aspen). Interestingly, I called Aspen and got someone who was completely clueless, but was supposed to be a technical support guy. All he could tell me was, "The coil is made of metal, and copper and 'whatnot'. I ain't never heard of that problem being solved."

Nice reply, and good to know the manufacturer has such skilled people waiting to help!---NOT

160 degrees F is considered "food safe" for many types of bacteria. gas furnaces aren't designed to raise your indoor tempurature that high.

and more so, 212 degrees F is considred when bacteria is supposed to be killed or not effective. and you're deffinately not going to get a furnace up to those temps.

[beachtech]

I've been living with the DSS for many years now and have done a ton of research on this subject. The one comment I read over and over again, old unit had no DSS, new install does. Thats what exactly happened to me. Old unit had no DSS for 15 years, new unit develops DSS in first heating season and have had it ever since. I believe the DSS is due to the use of these high efficiency type coils whereby the fins are packed tightly together causing an idea area for microbes to grow. From my DSS onset, my coil had always appeared shiny and clean, yet I have DSS in the defrost cycle which is so bad, it'll wake you from a deep sleep. Well its time for me to start my monthly winter coil cleaning, takes me about 4 hours to throughly spray and rinse the coil. Lasts about a month and then I repeat, at least by doing this the smell is tolerable. My unit is a Rheem which came with a 10 year parts/labor warranty. Rheem and its warranty has provided no help in addressing this issue, unlike some of the other manufacturers which are providing/installing coated coils to solve the problem. From everything I've read, coated coils are the solution. I have not heard from anyone with the installation of a coated coil have DSS return to their system.

only solution to the coated coils, is that the epoxy based substance that is used to coat the coil fills the pourus aluminum so that the bacteria is then "rinsed" off the coil during the AC cycle and during the defrost modes. the backside is that you will slightly loose some heat transfer of the coil and sacrifice some efficiency.

coil spacing and coil surface wasn't imprtant to us 15yrs ago, as energy was not a huge ordeal. but al gore put america in check with his ideals that he has completely retracted since winning his nobel peace prize... go figure lol

clear understand and common sense of thermodynamics tells us that a thinner peice of aluminum will really accept and transfer heat beeter than that of a thicker peice of metal that is space farther apart. No?

i think you can deduct where i am going with this....

[JBM1000]

First, it does not have to be a Heat Pump system, it can be just even cooling, or it could be just only strip heat and no cooling.

On down flow with strip heat, I have found Mold stacking behind the strip heat assembly plate and never sees burn off and is out sight of UV light.

This has been very rare to find and the only remedy is to pull and go back with new strip heat package & a good 100% system clean out.

The source is usually ground water via crawl space moisture, or slab ducts that have caved in and or fallen prey to rust holes. If so it can effect the evaporator every year.

On up flow system, can happen but not likely unless your environment is a basement and or just plain the area you live in is high moisture. Natural Well water under your home, ETC.

Mold could care less about gravity and will just appear when there is the right temp, lack of light, and a source of energy, (Food=Dust)

The answer is never cheap.

[HandyHank]

The last study on DSS from Trane states that the smell is a reaction to VOC's that exist with in the house that attach to the coil and then off gas during heat cycle.
It sure smells like mold growth to me though. And it seems to come only ever few years in my area of Florida. A good test is to cook the coil to 160 and then take a whiff, you will smell it if it's the coil. Cleaning coil with BBJ super foam & treating with BBJ C-1 Maintain does the trick on 90%. I have been advise before that you should not use a filter that is more than a MERV 8 rating? The customer usually only smells it from a few registers only and can also describe it as chemical smell or vomit if you can image that.
On one of our last DSS calls with a 10 year old Bryant unit, we cooked the coil and did not smell anything. So the Tech keep checking and found that the refrigerator was giving off a terrible musty smell . Opened the service cover and found a lot of hair in the defrost tray that smelled really bad. So he cleaned the pan and we will wait to see if complaint continues.

That was a great response, but how you you cook the coils?

[Sleuth]

Call a trained professional.


:callpro:

[HandyHank]

there are special coils used to replace those that have been determined to have the dirty sock syndrome..the coils are teflon coated,and are designed to retard the growth...i have replaced 2 in only 15 years in the field,but it has solved the problem both times

I am having the same problem with a unit that is only two weeks old. Actually it started a year ago with the brand new 16 seer Amana. The dealer blamed the smell on the uv light, so they removed it and replaced the coil. They claimed the uv light baked on the preservative the manufacturer put on the outside of the coil and that every time the heater came on it was reburning the baked on coating emitting the odor. So one would think that by installing a new coil without the light the odor would go away right? Thankfully we had an early spring and unfortunatly a very early Summeer. We never noticed any problem in the Summer except that they noticed it had a leak in the system somwhere. They were very busy as it was the peak of the summer so we agreed that if they kept the refrigerant level high so we stayed cool that they could work on it at their leisure. They came back in November & determined that the leak was in the coil. So in December they replaced the coil. When the new coil (now the third one) was installed we started smelling the horrible odors, the same ones they said was caused by the UV light back in February. The wife & I got horrible headaches whenever the heater was on and for a brief while after it shut off. She developed a very bad sinus infection which she continued to have for seven weeks. She had been to the doctor three times in five weeks in fact they thought hospitalization was in order just so they could get her into an environment that had better air so they could cure her. But we started spending nights with friends to get out of our own house. This convinced our dealer that there indeed was something wrong with this unit. He sent several of his workers out to verify the odor and they all got headaches and a bad taste in their mouth as well as a prickly feeling in their tongue & throat. So the dealer replaced the Air handler with the same model Amana.

Within a few days the odor has returned. Their Quality Air Specialist is workingon instaling a 50 cfm constant air ventilation as he thinks the problem is because of a pressue imballance in my house. This house is almost 35 years old and there hasn't been any problems up until I installed this Amana.

I've read here about teflon coated coils being the solution. Anybody have any experience with these and where does one obtain these? What manufacturer's sells them as part of their equipment?

After having to wear a mask just to stay in your own house and waking up tothe horrible odors of puke or a wierd chemical smell I don't know what else to do. My HVAC dealer says he's working on it but as long as I have to endure this each & every day at the cost of what I paid them to install this it is not fast enough. I contemplated consulting with an attornery to weigh my options because this is getting rediculous!

[teddy bear]

I had an old uncle with a terrible odor in his home. His kids blamed it on poor housekeeping. He died and the kids decided to remodel his 60 year old home. When remodeling the bathroom, they found a soil pipe rust off in the the wall. The hole in the pipe allowed soil gas into the home.
A side note, a home needs an air change of fresh air every 5-6 hours when the home is occupied. An a/c coil/ducts should dryout for a couple hours everyday to avoid mold/bacterial growth billed-up. Regards TB

[datgrt]

We had a new 3-1/2 Ton American Standard / Trane Heat Pump installed in January 2009. During the first heating and cooling season we did not have a problem with any odor. In November of that same year we did experience a very bad smell coming from the ducts every time the unit was running after the defrost cycle. I contacted the Dealer who installed our unit about the smell and he said that it sounded to him like we had "The Dirty Sock Syndrome". Never hearing about this issue before I did a Google search and read many of the pages of articles that had been posted about this problem online. After reading the posts about this problem there was no question in my mind that this was what was causing our smell! Prior to my internet research our Dealer had agreed to come out and 'clean' our coils which he did. Let me say that our Dealer is 'Outstanding' and the problem was not caused by anything that he had done it was caused by the company that made the unit!(American Standard / Trane / Ingersoll Rand) I shared with our Dealer that I appreciated him coming out to clean our coils but I didn't think that cleaning would solve our problem based on all of the posts that I had read online. Sure enough, a short time after he cleaned the coils the odor returned! I had already sent several email letters and made several phone calls to the National Customer Service Department of American Standard / Trane/ Ingersoll Rand about the problem I was having with our new Heat Pump. The responses I was receiving back from them were not good! Attached is part of the response I received back from them after my first email.

"Thank you for visiting our web site. I appreciate you sharing your concerns with us. There is an issue known as "Dirty Sock Syndrome" which occurs in the evaporator coil of some heat pumps during the defrost cycle. Dirt Sock is an environmental issue and not equipment related."

Believe me, I was not happy or satisfied with their response! How could the problem be 'environmental' when our old Heat Pump that we had in the same 'environment' for about 25 years never had this problem! After many more phone calls and email letters to the company they agreed to replace my coils! This morning (3/27/2010) my new coated coils were installed! I feel sure that this should resolve our problem with the "The Dirty Sock Syndrome" smell. I know and understand the problem the odor causes but more importantly are the health concerns and risks that everyone has when dealing with this issue!

The "Dirt Sock Syndrome" has been a problem for 'many' years and the companies that manufacture HVAC equipment are aware of the problem and they do have a fix for it. The problem is 'money'! They are not willing to put the more expensive coated coils in the units that they sell to avoid these problems in my opinion because of the increased cost!

Again, in my opinion cleaning the ducts or cleaning the coils won't fix this issue but I am not a Professional HVAC Tech! I believe that you should contact one of them for their help to fix this problem! I strongly believe that the problem is caused by the coils and the solution to the problem is to replace the coils with the new coated type! If it was not an equipment issue why would American Standard / Trane / Ingersoll Rand offer this as a solution to correct the problem?

I really hope that everyone that is experiencing this problem are able to get it fixed soon!

Thanks,
datgrt

[HandyHank]

I am anxious to know how your coated coil works out for you. I understand you just had it installed today, so you only have a few hours of use to formulate an opinion. But I have nothing other than what the dealer has tried and I still have the odor. Unfortunately the weather is getting warmer and as painful as it seems to not have resolved this smell issue I hate to run the heater when it is 90 degrees outside. But, so far they have changed the coil three times & the air handler once & I still have the odor, bad taste in your mouth when the heater runs, headaches, infected sinuses and burning eyes. Yesterday they installed a humidifier saying my humidity was too low so like you we only have had a day to see what difference it makes. But, on Monday of this week I did receive a visit from the district technical advisor for Amana/Goodman, the local dealer & his supplier and they all left scratching their heads. I have done mold tests on my ducts eliminating possibilites which fortunately were negative for mold. I also had my sewer lines scoped to ensure I had no broken or cracked lines putting sewer gases into the house (at times it smelled so bad in the house the dealer suspected sewer gas as the origin), but I got a clean bill of health from that inspection too. So you can see I am very anxious to know what the coated coils do for you for I will be sharing your results with my people. I hope your problem is resolved becaue it may offer hope for mine.

Thanks so much for sharing!



We had a new 3-1/2 Ton American Standard / Trane Heat Pump installed in January 2009. During the first heating and cooling season we did not have a problem with any odor. In November of that same year we did experience a very bad smell coming from the ducts every time the unit was running after the defrost cycle. I contacted the Dealer who installed our unit about the smell and he said that it sounded to him like we had "The Dirty Sock Syndrome". Never hearing about this issue before I did a Google search and read many of the pages of articles that had been posted about this problem online. After reading the posts about this problem there was no question in my mind that this was what was causing our smell! Prior to my internet research our Dealer had agreed to come out and 'clean' our coils which he did. Let me say that our Dealer is 'Outstanding' and the problem was not caused by anything that he had done it was caused by the company that made the unit!(American Standard / Trane / Ingersoll Rand) I shared with our Dealer that I appreciated him coming out to clean our coils but I didn't think that cleaning would solve our problem based on all of the posts that I had read online. Sure enough, a short time after he cleaned the coils the odor returned! I had already sent several email letters and made several phone calls to the National Customer Service Department of American Standard / Trane/ Ingersoll Rand about the problem I was having with our new Heat Pump. The responses I was receiving back from them were not good! Attached is part of the response I received back from them after my first email.

"Thank you for visiting our web site. I appreciate you sharing your concerns with us. There is an issue known as "Dirty Sock Syndrome" which occurs in the evaporator coil of some heat pumps during the defrost cycle. Dirt Sock is an environmental issue and not equipment related."

Believe me, I was not happy or satisfied with their response! How could the problem be 'environmental' when our old Heat Pump that we had in the same 'environment' for about 25 years never had this problem! After many more phone calls and email letters to the company they agreed to replace my coils! This morning (3/27/2010) my new coated coils were installed! I feel sure that this should resolve our problem with the "The Dirty Sock Syndrome" smell. I know and understand the problem the odor causes but more importantly the health concerns and risks that everyone has when dealing with this issue!

The "Dirt Sock Syndrome" has been a problem for 'many' years and the companies that manufacture HVAC equipment are aware of the problem and they do have a fix for it. The problem is 'money'! They are not willing to put the more expensive coated coils in the units that they sell to avoid these problems in my opinion because of the increased cost!

Again, in my opinion cleaning the ducts or cleaning the coils won't fix this issue but I am not a Professional HVAC Tech! I believe that you should contact one of them for their help to fix this problem! I strongly believe that the problem is caused by the coils and the solution to the problem is to replace the coils with the new coated type! If it was not an equipment issue why would American Standard / Trane / Ingersoll Rand offer this as a solution to correct the problem?

I really hope that everyone that is experiencing this problem are able to get it fixed soon!

Thanks,
datgrt

[datgrt]

I am anxious to know how your coated coil works out for you. I understand you just had it installed today, so you only have a few hours of use to formulate an opinion. But I have nothing other than what the dealer has tried and I still have the odor. Unfortunately the weather is getting warmer and as painful as it seems to not have resolved this smell issue I hate to run the heater when it is 90 degrees outside. But, so far they have changed the coil three times & the air handler once & I still have the odor, bad taste in your mouth when the heater runs, headaches, infected sinuses and burning eyes. Yesterday they installed a humidifier saying my humidity was too low so like you we only have had a day to see what difference it makes. But, on Monday of this week I did receive a visit from the district technical advisor for Amana/Goodman, the local dealer & his supplier and they all left scratching their heads. I have done mold tests on my ducts eliminating possibilites which fortunately were negative for mold. I also had my sewer lines scoped to ensure I had no broken or cracked lines putting sewer gases into the house (at times it smelled so bad in the house the dealer suspected sewer gas as the origin), but I got a clean bill of health from that inspection too. So you can see I am very anxious to know what the coated coils do for you for I will be sharing your results with my people. I hope your problem is resolved becaue it may offer hope for mine.

Thanks so much for sharing!

Hello HandyHank .......... Sorry to hear that your problem is not resolved! When they installed the new coils on your unit were the coils 'coated'? I will be happy to give you an update in a fews days to let you know if the new coated coils that were installed today fixes the problem for us!

Thanks,
datgrt

[datgrt]

I am anxious to know how your coated coil works out for you. So you can see I am very anxious to know what the coated coils do for you for I will be sharing your results with my people. I hope your problem is resolved becaue it may offer hope for mine.

Thanks so much for sharing!

Hello HandyHank ........ I wanted to give you a quick update. As I shared with you in my earlier note our new coated coils were just installed this past Saturday morning so we really have not had our Heat Pump running much since then. We did run it for a short time on Saturday and also Sunday morning just to check to see if the odor was still present. I am very happy to say that we have not smelled the 'Dirty Sock Syndrome' odor at all since the new coils were installed! It is too soon to say for sure that the new coated coils will prevent the odor from ever coming back but I really believe that they are the fix that we needed. Believe me, I sure hope so!

I hope you are able to get your 'DSS' problem fixed very soon!

datgrt

[conrad1]

Dirty Sock Syndrome exists in the cooling mode after the coil has been dry during the heating season, and from all info from current studies is a result of VOC's from cleaning solutions, or construction products even just gases released in the home from normal wear and tear of carpet, wood floors, sofas, etc... Follow The Advice In the Home Owners Manual and have your system serviced on a regular basis, by a reputable contractor and this problem will go away. Clean the coils change the filter on a regular basis you can use a standard poly filter and change it monthly or some pleats will last longer it all depends on how you live in your home. have the coils inspected each season and cleaned if need be or rinsed and sprayed with an industry and epa approved biocide.

[datgrt]

Dirty Sock Syndrome exists in the cooling mode after the coil has been dry during the heating season, and from all info from current studies is a result of VOC's from cleaning solutions, or construction products even just gases released in the home from normal wear and tear of carpet, wood floors, sofas, etc... Follow The Advice In the Home Owners Manual and have your system serviced on a regular basis, by a reputable contractor and this problem will go away. Clean the coils change the filter on a regular basis you can use a standard poly filter and change it monthly or some pleats will last longer it all depends on how you live in your home. have the coils inspected each season and cleaned if need be or rinsed and sprayed with an industry and epa approved biocide.

Hello Conrad1 ....... Based on our personal experience with our Heat Pump I totally disagree. For over 25-years our old Heat Pump never had the smell / odor of the Dirty Sock Syndrome and we had the same VOC's from cleaning solutions and the same gases that have been released in our home would or should have been the same. We have changed our filter on a regular bases and also had our coils cleaned by a trained Professional HVAC Tech and the smell was still there! It would be very hard for someone to convince me that it is not the coils that are causing the problem. Even the note I received back from Trane said that it was the coils.

datgrt

[conrad1]

I am sure that your old unit did not smell that way, but if your old system was 25 yrs. old It had considerably less coil surface for adherance of chemical deposits. Even though this is not a new phenomena it has been more prevelant (imo) since 13 SEER became the standard. And yes sometimes coating the coil will work it will also reduce your cooling capacities, some times it is not to drastic but in other cases it is drastic.

[datgrt]

I am sure that your old unit did not smell that way, but if your old system was 25 yrs. old It had considerably less coil surface for adherance of chemical deposits. Even though this is not a new phenomena it has been more prevelant (imo) since 13 SEER became the standard. And yes sometimes coating the coil will work it will also reduce your cooling capacities, some times it is not to drastic but in other cases it is drastic.

Hello again conrad1 ........ I respect your opinion but it differs from mine and that is okay! Based on all that I have read about the problem I also believe that the new High Efficient units are more likely to have the 'DSS' problem. Our new Heat Pump is a 15-Seer and I am more then willing to have my cooling capacities reduced if I can eliminate the odor!

Thanks, I appreciate your response!

datgrt

[96gsxr750]

The "Dirty Sock Syndrome" is caused by bacteria that collects and grows on the indoor coils of heat pumps and air conditioners.

Complaints normally surface when heat pumps go into defrost, or when systems are run in heating for a brief time then switched back into cooling. The bacteria or odor collects and grows on the coil during this heating time and is released all at once when the indoor coil gets cool and damp. Heat pump owners notice the odor when the system goes into defrost. Heat pumps and air conditioners experience the problem, when the air conditioner is turned back on after the heating has been used. Our climate can require heating in the morning and cooling in the afternoon. This is a perfect condition for a complaint to surface.

Action can then be taken to resolve or reduce the complaint, starting with a thorough cleaning of the evaporator coil with a non-acid coil cleaner. Cleaning will bring the system back to normal and will usually prevent a complaint for the rest of the heating season. Some systems cleaned early in the season or those having more of a problem may have repeated problems during the same season, especially if the weather conditions force a system back and forth from heating to cooling. The majority of complaints are resolved with a thorough cleaning.

If the coil cleaning does not resolve the complaint to a satisfactory level, the next thing you could try would be to clean the coil again and apply a coating of Alathene II, a special spray designed to continuously protect coils from fouling caused by airborne contaminates. Past that there is not anything you can do since it is an environmental issue that is causing the bacteria to grow and accumulate. If anyone else has any other information about this please post up.

[pmeunier]

... If anyone else has any other information about this please post up.

The requirement for biomass accumulating in the coils means that better air filtration can keep the coils clean longer.

[jrearly]

My Trane home A/C XB90 system has a coil in the crawl space under the house Model TXC061C5HPB2 (Serial N361KG65G).
There is a steady stream of water coming out of the duct end of this unit, and there is considrable rust there, and water is running out of the other end in the area adjacent to the drain tube, but very little coming out of drain itself. We have mold in joists over the unit, very high humidty in the area, and musty smell coming out of the house ducts closest to the unit.
Please tell me what could be wrong. My HVAC serviceman says it looks normal

[teddy bear]

Any wet surface that does not have a consistant flow of water removing dust and biological growth has potiental for growing odor producing biologicals. Clean a/c coil with steady condensation flushing the surface seldom produce odors. Stagnat corners in consensation pans or wet spots in the ajoining ducts or under bracket grow bioloicals.
I have fixed several by eliminating the wet spots and thoroughly drying the coil/ducts for several hours everyday. After eliminating the wet spots by repositioning the pan to drain perfectly and eliminating wetting of the other material in the ducts, operate the blower "on" mode to provide extended drying time. Also confirm that you are keeping the air in the home <50%RH. in green grass climates, supplemental dehumidification is needed during wet cool weather to maintain <50%RH. The more difficult cases may require a ducted dehumidifier blowing dry air into the air handler to quickly dryout the space between cooling cycles. I have had this odor coming from humidifiers that are wet for extended times without enough over flow to flush the biologicals off the element. Depending on the particular bacteria, odor will vary. Some are slimey but oderless.
Regards TB

[jrearly]

TB, thanks for your reply.

But the Trane model TXC061C5HPB2 is under my house in the crawl space.
Why would water be running out of the unit in a corner next to the drain tube and in a closed part of it where the air ducts first connect to it? Do these units ever need cleaning? Is it a maintenance item? Is there a procedure for cleaning it?

thank you very much

John

[teddy bear]

The unit may have not been installed right originally. Or the pan has rusted through? Have a a/c tech check it out for proper pitching to drain properly. Regards TB

[mrfixinthangz]

You need to clean your socks more often the dirty sock smell migrates towards them and they catch it. Seriously have the coil sprayed and cleaned more often than someone who does not have the same fungus in their home.

[bbjenviro]

Dirty sock syndrome is usually caused from some sort of biological growth coming from the heat pump. This odor can usually be controlled by using an antimicrobial to control the growth of mold and bacteria. There is a product called BBJ Maintain C-1 for HVAC/Air Ducts that can be applied once the unit has been cleaned and it will prevent growth. This product has been found to be effective at eliminating "Dirty Sock Syndrome" in 80% of the cases.

[richfrush]

:deadhorse:
This problem is as old as creation itself.
"Mold" grows in dark, damp areas and like everything else, it stinks when it dies and sometimes when it is alive.
The cowboys and settlers didn't have this problem because they didn't live in airtight boxes and they regularly filled their noses with things that allowed them to appreciate a warm or cool place to sit that wasn't wet or frozen.
This thread has been going on for several years and lots of suggestions have been posted. Truth is, there are many potential causes for these symptoms it is nearly impossible to eliminate them all. Some of them can be reduced.
I have read most of this entire post and don't recall anyone asking about the physical installation except jrearlys equipment installed in a crawl space under the floor. His condensation pan needs to be cleaned and check the outlet for the blockage causing the water to be "leaking" anywhere other than through the outlet.
So many problems -- so few answers....

[bbjenviro]

I agree with richfrush. There are many possible situations. One can only diagnose the problem by visiting the site and inspecting all areas. When it comes to Mold Remediation, source removal is always the first step, and then some form of preventitive maintenance should be used in order to prevent a reoccurence.

[Martin 2010]

If you want the problem solved, replace the coil, ideally with a different manufacturer and add a high MERV rated filtration system to the return side of the system (go as high as you can, watch pressure drop).
The other option is to kick the pet or the human that carries the bacteria out of the house. Usually not possible, but in some cases a divorce brought the pleasant side effect of solving DSS.

Good luck,
Martin

[KOTM]

Martin 2010: You could be right, but the reasons I think that the suggestion that someone in the house carries a certain bacteria that has spread to the AC system is an isolated incident with no meaningful cause and effect . . . are so plentiful that I don't have time to mention them all. But I will mention a few:

My wife and I have not changed our habits over the last several decades and certainly not at all over the past two years. And we have not had any pets in this home. Nor has there been any tobacco smoke. And we have always kept the house very clean (dusting, vacuuming, etc. regularly). And neither of us has been sick for at least four or five years (and then just a cold which is a virus). AND our old system (a builder's grade air conditioner with a gas furnace) ran for the entire eleven years we were here with NO DSS. AND our system before that ran for about sixteen years before we moved and was still working when we left with NO DSS. So, we got completely new systems (except for the ductwork) put-in two years ago (our first heat pump) and now we do HAVE DSS.

The other reason I think this explanation of human cause is incorrect is because I think I know the original source (of the divorce anecdote); and I think it was--perhaps true--but just an anecdotal aberration. Plus, I have been reading about DSS now for hours each day for a while now and have seen many stories similar to mine--so although mine is also anecdotal, there are many others so similar that I think the correlative weight is on the side of there being something wrong with the systems or the installation of the systems rather than the inhabitants of the home.

[KOTM]

Martin 2010: you say watch the pressure drop. I suppose this is the same thing as saying be sure the static pressure is not too high? Since my static pressure is now .7, I plan to remove the Clean Effects and just rely on a MERV 13 Aprilaire 2010 5" media filter (I am now double-filtered with both).

How low should the static pressure be in your opinion? I was told that the installer aimed for .2 or .3 and felt good about .4 and OK as long as it did not rise above .5 (of course he changed his tune after he found it was .7 and said this advanced system was designed to run as high as .9 with no ill effects. I suppose proper vent types, and correctly sized and installed ductwork also affect the static pressure.

note: my Trane system with the problem smell: XL16i (2 ton heat pump), 2-1/2 ton coil (oversized), and XV80i (60,000 btu gas furnace). My other Trane system (which I think probably also has the DSS problem but not as bad yet): XL16i (3 ton heat pump), 3 ton coil, XV80i (80,000 btu gas furnace).

[trail rated]

I have recently had DSS on my own HVAC system, a 3 year old Nordyne P3RD. I had tried a few of the top disinfecting coil cleaners but the smell would go away for a few days and then come back. I know this is a big no no in HVAC but I was able to remove the smell by scrubbing the coil with a 10:1 ratio of water/bleach and cleaning the coil with Coil-Rite. I can assure you that the coil is undamaged and smells clean. The bleach was thoroughly rinsed off with warm water a few minutes after it was applied to ensure there was no residue left.

The reason I did this is because the system is out of warrenty, so either I replace the coil because of DSS or I replace the coil because of corrosion if bleach would have damaged it. Thankfully, I didn't have to replace the coil at all and I have been DSS free for over 6 months.

Be careful, I wouldn't do it if the system was under warrenty.

[ewang]

Could it be low system airflow?
Could the AC system be sized too large?

Either would cause the AC system to cycle On/Off repeatedly, raising the humidity level, contributing to the smell?

[Jely]

The filter wont have any play on what type of smells your coil may be producing. Now a cheaper filter will allow more dust/allergens/agents to coat your coil possibly increasing odors emitting from the coil. Thats why it is key to buy an efficient filter for protection. Don't ever let someone tell you to buy a cheap throw away! As far as the dirty sock syndrome goes it really happens what would seem randomly in homes. A coated coil does help this issue. Usually the smell fades after several cycles. No harm being done. All depending on the style UV light system you had installed and the radiation intensity you may be getting full benefits from the UV, or next to none. Consider the UV light like a tanning bed, you cannot have it partially tanning you and expect the same results. Full coverage is key and most UV systems out there only apply close to 40-60% coverage. if that!

Want an efficient filter geared to last and protect your system?

www.enviromaxfilter.com

[Great white Shark]

After 13 years of discomfort each summer and thousands spent!!! Thinking I had Dirty sock syndrome or a dirty coil
Great news, the plumber found the source of stink (sewer gas) entering my house via positive pressure.
Plumber did smoke test on sewer line today, be for any work was started. It revealed that indeed the sewer gas was not making it past condensation p-trap, but was coming from a uncapped T in the vent stack that was intended to be used to run A/C condensation line when house was built and a unit installed 30 years ago. That said stink is no more!
“So sad, but so true “

[jbow52]

In the last year or two I have been noticing "the smell" mostly in the first of the winter. This morning it was particularly bad and I have been asthmatic all day. I have noticed some small puddles at times in the crawlspace and will look into a fix. I think my system is a Trane but am not going to go look right now, any case it is HE, this house was built in 2004 and it was built with everything HE in mind... (I can't wait to find out what probems the new lightbulb police cause). I am going to make a call and get my coils cleaned next week.. however...

The real purpose of my post is to throw something into the mix that may help. I found this prduct when looking for something to treat the housedust problem in my parents home. I get pretty bad allergic reactions if I begin to look through anything there, they live in south GA, about 60 miles north of Tallahassee, Florida. It is very humid there, there is plenty of "old book smell" on things. My eyes swell and itch if I look through old school annuals or other books from there. I researched online and found that it is a fungus. Then I found a product that claims to treat rooms, crawlspaces, whole houses, or a container with some books in it. I ordered a pack to treat some books but have not used it yet. After wheezing and coughing all day today and figuring it has something to do with the nasty smell from the heat pump this morning I looked the stuff up again.
The ingredient is CLO2 and it is a slow release. I would assume you wouldn't want to use it in any place with a pilotlight. I am an exterminator andam always concerned about pilotlights when dusting or fogging... but anyway... the company is OdorXit and they are here: http://www.odorxit.com/?ucatalog&prod=clo2s
I don't know if it will work but I may try getting the correct ammount for my crawlspace when we will be away for a few days. Maybe open up the case to the crawlspace unit and let it work the whole crawl for a few days. It is supossed to kill fungus and spores.
Has anyone tried this or does anyone know anything about it? I looks like it might work to me.
I will try to get off my rear and treat the books next week to see hw well it works on them.

Thanks,

Julien in GA

[teddy bear]

I suggest monitoring the %RH in your home and crawlspace. If the droplets of moisture are on the earthside of plastic moisture barrier, not to worry. If the droplets are on the top of the moisture barrier, close the vents and get a good dehumidifier going to reduce the dew point of the air. You should be <60%RH in the crawlspace. Plastic vapor barrier, closed vents to the outside, and some dehumidification will keep the crawlspace <50%RH.

For the home, suggest <50%RH in the home. During high cooling loads, the a/c should be able to do this. During the shoulder season, a whole dehumidifier is ideal.
If you heat pump has extended wet spots in the pan, expect potiential wet sack. Clean throughly and avoid extended wet spots. A whole house dehumidifier or operating the fan in the "on" mode during the heating season may help.
Regards TB

[victor61]

This unit was installed in Apr '09. Contractor tried cleaning and UV lights. There has been some minor mitigation, but the phenomenon persists. UV lights help some, but can't hit all surfaces. I'm now back to getting bids on an LP furnace, using the coil only in AC mode in the summer. Expensive, but little else to try now, I guess.

Anyone know if the Trane coated coil can be coupled to a York Heat Pump. (I think the coil is actually an Aspen).

Frustrated beyond description.

[KOTM]

I had DSS. I got coated coils (new from Trane, no charge, under ten-year warranty). Now, no DSS. But, something worse. I'll call it CCS (coated coil syndrome). There is now a musty, dusty, pungent, sickening smell accompanied by a metallic taste and irritation to the lungs. The "smell" part is not near as bad as DSS (I could live with the "smell" part of CCS); but the "effects" part is much worse. If I stay in the house for hours, my eyes sting (a little), I get a headache (slight), I get dizzy (a little), I can taste the metallic taste (slightly), and my lungs get irritated (a little). If I stay in the house all day, the smell and the effects are cumulative and I feel like the effects are making me sick.

This effect was very strong in the beginning (a few weeks); such that I HAD TO open all the windows AND leave the house. Then, it seemed to lessen gradually over the next couple of months and I thought it would go away. It has now been about nine months and the CCS is not nearly as strong and I cope with it routinely now by opening the windows at night for about an hour (with all systems completely off) before going to bed and leaving them off all night.

It seems to me that the coated coils are off-gassing something in the coating; and I am hoping that it eventually dissipates entirely . . . before it kills me through the cumulative effect on my lungs.

The product was Bronz-Glow coating of new Trane coils. It was slightly tacky the day the technician installed them (two systems) and the smell was evident even before they were installed (emanating from the coils). They were coated at ASI Coatings in Semmes, Alabama. They and the parent company are pretty closed-mouth about what it might be . . . claiming that I am the only one who has ever complained and that their product is perfectly safe and effective.

I did discover one large A/C company (Central City Air) in Houston, Texas that recognized the problem and said that in their experience it would take about two years for the off-gassing to dissipate and that they had learned to solve the problem by replacing the offending coated coils with new uncoated coils that were NOT A-coils, but WERE slab coils and that the slab coils did not need to be coated because they would not develop DSS in the first place like the A-coils would.

Any further information or help understanding and/or solving this problem appreciated.

[victor61]

If that doesn't work, am considering a coil coating by a company called ElectroFin. I do hope it's not the same as the Bronz Glow coating process that you mention KOTM. You have me a bit worried now. I cannot imagine dealing with this new problem of eye irritation, etc. that you mention. Let me know how this works out.

The slab coil approach is interesting. I no longer care about efficiency. Can one get a slab coil where currently an a-coil is installed? My set up is an upflow unit in the basement. Who makes a slab coil that would fit, I wonder?

Am at my wits end with this DSS. The dealer has given up, and just wants me to go away. The LP furnace strategy is problematic due to tank placement, etc. (and very expensive).

victor.adams@gmail if anyone wants to contact me directly.