Musty Smell Dirty Sock Syndrome

[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]

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.