Dirty Sock Syndrome?

[kcmk]

In our house for 12 years, with the original 17-yo 3-ton Bryant AC/coil/100k BTU furnace, we never had an odor of any kind. Two years ago, late Aug. '03, we replaced the Bryant AC and coil with a 13-seer 3-ton Trane. It ran very little until the next spring (of '04). Ran fine throughout the cooling season of '04...up until Oct. '04. Went for a few days without AC, then during a warm stretch, we turned AC back on....didn't work. Dealer tech. found a wire fried in my disconnect box, fixed it, cleaned furnace burners, and turned back on. Holy Scnikies! The entire house was filled with the odor of dirty feet/socks. It also seems to have an allergic effect on me (puffy eyes, tight chest, etc.). Dealer/Trane replaced coil only, not housing, in Nov. '04. Ran fine during cooling season of '05...until Oct. '05. Same scenario again this fall...dirty foot smell.

Dealer and Trane have no answers, other dealers all want to sell me their systems. Will I continue to experience same problem with their's? Had an air monitor in house, nothing unusual (including normal humidity). System seems to be sized right, according to most of the load calcs the dealers did and according to what was in the house originally. Duct cleaner/mold remediation person suggests it has something to do with the coil. I tend to agree. If you pull back the front cover from the coil housing, it stinks in there.

Do UV lights really work to kill mold, etc. on coil and in pan? Any other suggestions?

Kevin

[Edited by kcmk on 11-09-2005 at 02:31 PM]

[Steve Wiggins]

Do you have any organic (food) material close to the return intake? Maybe a food dropping or dog food bowl etc...?? Organic material can start the mold process and the defrost of the coil provides the water needed ...temp during defrost is just right also.

[kcmk]

Originally posted by Steve Wiggins
Do you have any organic (food) material close to the return intake? Maybe a food dropping or dog food bowl etc...?? Organic material can start the mold process and the defrost of the coil provides the water needed ...temp during defrost is just right also.

This is NOT a heat pump. Nothing near the returns, they are high on the walls. No pets of any kind. Nothing in ductwork, other than small amount of dust accumulated over 20 years.

[Edited by kcmk on 11-09-2005 at 12:10 PM]

[Swabby]

kcmk, sounds like your smell problem started when the guy did the repair to the disconnect and did the cleaning. Did he, also, do a cleaning of the indoor coil? You might want to get back to that person, if possible, and see if he did and see if you can find out what he used to clean the coil with.

[kcmk]

Originally posted by Swabby
kcmk, sounds like your smell problem started when the guy did the repair to the disconnect and did the cleaning. Did he, also, do a cleaning of the indoor coil? You might want to get back to that person, if possible, and see if he did and see if you can find out what he used to clean the coil with.

Did I mention that last fall (Nov. '04), right after the first occurrence of odor with the new Trane coil/AC, that the dealer replaced the coil with a another new one? Again, the same thing happened with this coil this fall (Oct. '05).

The tech did treat the first new coil with a spray foam (some kind of germincide?). When we turned the AC on, it smelled the house up with the smell of the spray. But that coil was replaced with another new coil...with no special treatment applied to it.

Kevin

[Swabby]

Sorry I missed that point. Just trying to help.

[ductguy007]

Are your supply grills in the ceiling or the floor?

[kcmk]

Originally posted by ductguy007
Are your supply grills in the ceiling or the floor?

Supply vents are on the floor, returns are on the walls about 7 feet up from the floor.

Does anyone have any thoughts on WHY this is happening? I think something is growing on the coil and/or in the condensate pan. Wouldn't a UV light solve this? My impression is that UV lights are worthless for killing anything airborne in the plenum. But if something is growing on the coil or in the pan, and the light is shining directly or evenly indirectly on it, shouldn't the light kill it?

Kevin

[Edited by kcmk on 11-09-2005 at 01:19 PM]

[ductguy007]

Ok:Here is why the odd question.Now I know that you have a down-flow system.What might be happening is that when they installed the new coil ,there may be a condensation problem.Your supply plenum is under the coil.If the primary condensation is plugged,your drain has to go somewere.The drain pan in the coil might be over-flowing into your supply ducting making kind of a wet-sock,wet insolation odor.I have seen standing water in supply ducting for years. Here are some tips that might help you:
Look under your home for excessive duct sagging near the supply plenumm.If found contact the company that installed the coil-have them drain/repair the ducting,blow out the drain,make sure that the drain has flowing grade.

Another odor problems could be:#1Rodents in/around the ducting-both supply and return.#2 Sewer venting problems.While under the house,do thorrow check around the bathrooms and the kitchen.#3Standing/staggnent water under your home. I hope this info helps
Good-luck.

[ductguy007]

Oh ya! about your U.V light question? Ultra-Vilot lights are great,but hold off until this odor problem is resolved.

[kcmk]

Originally posted by Swabby
Sorry I missed that point. Just trying to help.

No problem Swabby, I am open to all suggestions.

Kevin

[kcmk]

Originally posted by ductguy007
Ok:Here is why the odd question.Now I know that you have a down-flow system.What might be happening is that when they installed the new coil ,there may be a condensation problem.Your supply plenum is under the coil.If the primary condensation is plugged,your drain has to go somewere.The drain pan in the coil might be over-flowing into your supply ducting making kind of a wet-sock,wet insolation odor.I have seen standing water in supply ducting for years. Here are some tips that might help you:
Look under your home for excessive duct sagging near the supply plenumm.If found contact the company that installed the coil-have them drain/repair the ducting,blow out the drain,make sure that the drain has flowing grade.

Another odor problems could be:#1Rodents in/around the ducting-both supply and return.#2 Sewer venting problems.While under the house,do thorrow check around the bathrooms and the kitchen.#3Standing/staggnent water under your home. I hope this info helps
Good-luck.



We're confused. I thought I had an upflow system. Air vents on floors, returns high on walls, air return drop feeds air into bottom of furnace, pushed up through furnace by blower motor, up through coil, and up through plenum, finally into main duct trunk. That's upflow, right?

Condensate pan tube is flowing water, drain cock betw. pan and tube is free of obstructions, and there is no evidence of pan ever overflowing. It does seem as though the pan is slow to drain and retains water. I wonder if the pan is not "tilted" enough in the right direction, to feed the water toward the drain cock and tube? This could provide a breeding ground for nasties!

Kevin

[james mo]

Do you have a bypass humidifier installed?

[classical]

Do a search on DSS you will find it discussed to death.

"UV" lights will not help the situation and they are basically a worthless addition to any system.

DSS comes from the house and will occur on any coil you have installed regardless of brand.

The best option so far is either seasonal cleanings with several different products or having a coated coil installed.

There are several companies that coat coils one is Technicoat (Texas) the other is Bronz-Glo (Florida) there are others just don't know their names.

Bronz-Glo has a fairly effective product that can be applied at the home it is in a spray can. The best option is to buy a coil already coated and have it installed. Trane should have a Technicoat option if your contractor will check.

There is a company here in Texas that has products for cleaning and treating coils. I haven’t used them yet but the literature is interesting they have a generator that will fog your system and kill mold and mildew spores. I will find a link for you in the next day or so.

[ductguy007]

Sorry if I confused you.Up-flow= air blowing out of the ceiling grills in all rooms,Return=draws air in at the base of the furnace. Downflow= air blowing out of the floor grills in every room and Return=draws air into maybe one or two large ceiling grill. Good Luck.

P.s If U.V lights are so bad,why do so many Medical facilities use them. Again solve odor mystery first than do the homework on U V products.

[docholiday]

As mentioned DSS is very difficult to treat and as much as I hate to say it, TRANE has nothing to do with it. It is basicly a mold that is growing in your system that is a result of somthing in the environment. You need to ask yourself, has anything else changed? New carpet, paint, animals, critters, cabinets, change in laundry soap?

Its very difficult to tolerate but you may be in this for the long haul. UV lights, may slow the growth provided they are properly maintained and completely wash the coil in light but I dont think they will solve an exsisitng issue very well.

I would start by verifying the drain pan is slightly tipped toward the drain and not holding any water, and be sure to have the coil chemicaly cleaned with a good coil cleaner, one that requires rinsing, the self rinsing ones are not strong enough. Lysol may also be a consideration to help eradicate what is already there.

[hvacsac]

you might need to put a PCO from lennox or a accuclean filter(american standers) clean effects (trane) the smell will take time to go way with pco but it works ,i haven`t tried the accuclean but i hope someone can tell us more about it.

[mark beiser]

The ultimate solution is a coated coil, but Nu-Calgon makes a couple of products that seem to work very well if applied during regular maintenance every year.

I don't run into it very often, but have had it develop within weeks of a new install before. Usually it is limited to heat pump systems, but happens on straight AC coils sometimes too.

We have had it develop in 3 systems we installed in the last 4 years. We just order a new coil and have it coated, or order a coated coil directly from Trane. Trane gave us new coils under warranty, but didn't pay for getting them coated, exept the one that we got already coated.

[classical]

The reason 007 that "UV" lights don't work in most residential systems is application. In order for a "UV" light to be of any benefit it must have residence time on the particulate it is trying to destroy. Since air is moving at 500 FPM to 1000 FPM there is no residence time for mold or other spores in the air stream. It will kill whatever is on the coil if there is a strong enough light on both sides of the coil. No light available for residential is strong enough to penetrate an evaporator; therefore it requires two lights. In addition in order to eliminate odor it must produce ozone, which in high enough concentration to kill mold or eliminate odor is uncomfortable or harmful for many people mostly small children or seniors.

"UV" light will also break down any petroleum based product in the system that if shines on. That means PVC drain pans; flex duct, glue and wiring.

There reason the lights work in hospitals is they are used for specific purposes like in laminar flow microbiological hoods. In these applications they are used to bathe an area in light to keep biological from growing not to clean the air stream. There are large models that are very expensive designed for commercial duct systems that can affect an air stream but they are large and expensive. The reason they work is due to their size and design they provide close to 40 seconds of residence time which needed to kill biological material.

I f you will search this site for DSS and "UV" lights there are numerous links concerning this subject.

[teddy bear]

I fix DSS on my hp system. Found a non-pitched drain pan with two 2"X14" wide flat sheet metal cooling coil brackets laying flat on the pan. They retained moisture between the pan and bracket between cooling cycles. The wet area remained wet for extended periods like the entire cooling season. I pitched the pan, elevated the bracket, and operated the fan continuously. This eliminated DSS.
I believe you have a high moisture area in you cooling coil/ducts that is not drying out on daily bases. When the particular odor generating biologicals get started and dominate, you have the problem. Find the wet spot, clean it, get it do dry routinely during the off cycles. No more odors. Operating the air handler fan beyond the cooling cycle dries out proper draining cooling coils/ducts but elevates the %RH. Using a whole house dehumidifier to dry out the a/c coils/ducts between cycles quickly. The dehu also maintains dry home/cooling system during low/no cooling load times which eliminates most of the biological growth problems in a home. TB

[ductguy007]

Classical: Two thumbs up on the info on U,V lights in residential systems.You pointed out some good factors.
I have installed U.V lights for a number of years.It is funny to see here in HVAC land Who favors them and Who does not. Just a couple of things for my own info:
If there is standing water in the drain pan and you have a remote bulb installed in the Delta Wall,Wouldn't the germicital light take care of things? The drain pan is made of galv sheet metal,and the newer pans are made of special material that the U.V will not break down,like a out-door c/u slab. The only time that I have ever seen damage is when someone installed the light in the R\A -Like flex break down,fadded carpet,wire inso problems. I even heard of a customers dog lying up against a R/a grill. Any way I Hope they find there odor and get back to us. Take care.

[kcmk]

Originally posted by james mo
Do you have a bypass humidifier installed?
No humidifier installed. I didn't see a need for it, as the AC's on the market today are twice as efficient as my old Bryant was. That will (if anything) only cause the AC to reach the desired thermostat setting earlier and kick the AC off before it has had time to dehumidify the house. That would only promote more growth of nasties!

Kevin

[dash]

UVC lights, have woorked for us on DSS cases ,most not all of the time.

The need to completly illuminate the coil on the leaving air side,they can't treat the air as stated,it is moving to fast.It may take two lights on an A coils or larger sloped coil.

[kcmk]

I didn't realize this was going to be such a popular topic for discussion. That's good....as I am looking for answers. No offense to anyone, but I am past the point of sales pitches (not that anyone on this board has pitched any). Nearly everyone that I have conferred with, either in my home or via phone, has had something to sell...but no one yet has given me the confidence that they know what is causing the problem, nor that by purchasing their product(s) will I resolve my problem.

Re: comments about the UV lights, I have considered many of them already. I believe that the lights are worthless...if one's intent is to kill airborne particles in the plenum. My purpose would be to kill anything on the coil or in the pan. I was concerned about any environmental/health risks associated with the lights, however. The lights are expen$ive...usually around $550-600, and the bulbs are $80-140 each (x2 if you have a dual bulb model...which only makes sense if you have two sides to your coil, as I do).

I have heard of "coated" coils before. I will check into that tomorrow with Trane. I am also going to try to get the original dealer back out here to check the installation of my coil/pan, for proper drainage.

Two more question:

1) If you already have something (maybe mold, maybe not) growing on your coil/pan...can if be removed effectively, or do you need to replace with all new equipment and start from scratch?

2) Does running the fan all the time really help? It would seem to me that it would, as it would provide a constant flow of air across the coil/pan, thereby dissipating any residual moisture that much more quickly. This is only during the cooking season, right?

Kevin

[Irishmist]

So what do you do when you have DSS and it's associated with the locker room system?

[Mr HVAC41]

Originally posted by kcmk

This is NOT a heat pump. Nothing near the returns, they are high on the walls. No pets of any kind. Nothing in ductwork, other than small amount of dust accumulated over 20 years.




i see a problem here

perhaps the airflow from the new system has been breathing harder than that bryant!

[kcmk]

Originally posted by mr hvac41

Originally posted by kcmk

This is NOT a heat pump. Nothing near the returns, they are high on the walls. No pets of any kind. Nothing in ductwork, other than small amount of dust accumulated over 20 years.




i see a problem here

perhaps the airflow from the new system has been breathing harder than that bryant!

Please explain.

Kevin

[ductguy007]

KCMK:It seems that we are kind of jumping around from from the original post: Odor Is the smell in both heating and cooling modes?.Is the Odor present when the system is not running? And Has the Heat exchange be tested for Cracks?

[ductguy007]

Forgot to ask:The grills in the floor-Are they blowing air out or are they sucking air in? Confused!!!

[Mr HVAC41]

This is NOT a heat pump. Nothing near the returns, they are high on the walls. No pets of any kind. Nothing in ductwork, other than small amount of dust accumulated over 20 years.


i see a problem here

perhaps the airflow from the new system has been breathing harder than that bryant!

Please explain.

Kevin

------------------------------
kevin, your old system was settled in right? as the system ages, it gets dirty and breaks down and wears out. its kind of like driving a car for a while, its really neat and does all this stuff and over time, you just dont take notice. then you get a new car and wow!

i think you understand. if not let me know

[kcmk]

Originally posted by ductguy007
KCMK:It seems that we are kind of jumping around from from the original post: Odor Is the smell in both heating and cooling modes?.Is the Odor present when the system is not running? And Has the Heat exchange be tested for Cracks?
Air vents are in the floor, returns are on walls (approx. 7' up from floor). Odor occurs when cooling, especially if system hasn't run for a couple of days. Can also smell it during heat, but only after AC has run just prior to heat. Furnace burners were cleaned last year...supposedly the tech checked the heat exchangers...but then, this is the same dealer that installed the system, and I don't have much faith in them lately.

I spent yesterday afternoon removing and thoroughly cleaning the furnace blower motor and housing. Wow! It was dirty after 20 years. Nothing hardened on there, but the veins had a great deal of dust accumulated on them. I also cleaned out the lower furnace section (around the motor) and the bottom of the air return drop. I noticed one of the three wires to the blower motor (where these wires have clips on them that plug into one large multi-port clip that is part of the motor's wiring harness) had shorted/burnt. The blower still works, but I wonder what caused this, if it is still burning/shorting, and could it be causing an odor?

Kevin

[ductguy007]

Do you remember the days when we put that cassette player in our first ride back in High-School,and we used electrical tape instead of wire nut's? Ohh that smell! It very well could be that the Blower motor is getting ready to go Bye-Bye. I do not know what part of the States that you are in,but im sure that there is a good HVAC'er in your area.Check with the B.B.B and your State Contractors Web-site ,to find a quality Contractor. Good Luck.

P.S still Confused: If you set a piece of tissue on the floor grill,Do they suck in,or do they blow away?

[Mr HVAC41]

i believe he said its only in cooling that the smell reaks its head into the house. try again 36 poster!

[ductguy007]

Just try'in to help the guy Mr41--I guess if I had 600 Blond jokes,16-Wall of shame post,and one Petty posting Maybe i'll be caught up to ya Ha-Ha WWWWWaaaaa

[kcmk]

Comeon guys, let's keep it friendly. Ductguy, I have an upflow system, if that's what you're asking. There is a very interesting thread in the "Air Quality" section of this forum, started by Milkman's Daughter. Apparently, she (they) have the very same problem as I do, and it reappears at the very same time of year as my DSS problem...fall, when the AC is used more sparingly.

Kevin

[Mr HVAC41]

Originally posted by ductguy007
Just try'in to help the guy Mr41--I guess if I had 600 Blond jokes,16-Wall of shame post,and one Petty posting Maybe i'll be caught up to ya Ha-Ha WWWWWaaaaa

dont forget the 5 about arcoaire! lol

[ductguy007]

KCMK:It's all in fun HVAC41 has some good posts on this Web-It's expected- im the new kid on the block-Ha-Ha.
Back to business.
Running out of options: If it is not the Insolation on the fan motor wires-Remember your in-door fan run's at higher RPM's for cooling than Heat, Two of the worse smells in HVAC are dead rodents and wet insolation .Is the new coil installed in the old Houseing? I have had alot of calls were someone has added A/C to a Heat only system and the fan blew so hard that the condensation running down the coil would blow on the internal insolation,soaking it giving off the wet sock smell. As posted in the past,Check with the B.B.B in your area for a good company with referances, that also offers Power -Vac and Sealing as well as HVAC service. Best of Luck.

[kcmk]

Originally posted by ductguy007
KCMK:It's all in fun HVAC41 has some good posts on this Web-It's expected- im the new kid on the block-Ha-Ha.
Back to business.
Running out of options: If it is not the Insolation on the fan motor wires-Remember your in-door fan run's at higher RPM's for cooling than Heat, Two of the worse smells in HVAC are dead rodents and wet insolation .Is the new coil installed in the old Houseing? I have had alot of calls were someone has added A/C to a Heat only system and the fan blew so hard that the condensation running down the coil would blow on the internal insolation,soaking it giving off the wet sock smell. As posted in the past,Check with the B.B.B in your area for a good company with referances, that also offers Power -Vac and Sealing as well as HVAC service. Best of Luck.

No rodents...we probably have the cleanest house in America. By "isolation" I assume you mean "insulation"...as in the insulation installed on the inside walls of the coil housing? When the dealer installed the first new coil, in '03, they installed all new housing. When they came back last year ('04), after the DSS symptoms began, and they installed another new coil, they only installed the coil and not another new housing. I thought about the insulation as well. I removed a small section of it, dampened it with water, waited a while and then smelled it. There was no odor whatsoever.

[coolcray3]

ok here it is trane came out and and replaced the coil and not the coil casing and it had a smell why didnt they change the coil case there is insulation around the inside of the coil case isnt there could it be that the insulation got wet or the furnace insulation the ac worked fine the first season and not the next.i have had to replace coils that were bad on some new installs and found that the insulation around the heat exchanger had not been glued well and the insulation fell onto the heatexchanger and melted the foil backing and the plastic adheasive behind it and i know that had to give off a bad odor so if every cooling season the insulation is pulling away and lying on the heatexchanger and burnning and thats where the smell comes from the humity probably activates it every seasonand more insulation falls every ac season and burns every heating season

[coolcray3]

also what type of fuel is the furnace and does the coil have ametal pan or resin pan

[kcmk]

Originally posted by coolcray3
also what type of fuel is the furnace and does the coil have ametal pan or resin pan
Pan is white plastic/resin. Furnace is gas forced air. I doubt the furnace insulation is the culprit. The smell is not that of anything burning. The smell is a musty dirty foot odor smell. The dealer put a new housing in with the first new coil. Why the dealer did not replace the housing, when they put the second coil in, is anybody's guess. Goes back to one of my first comments regarding my lack of trust in this dealer.

Kevin

[davetec]

Does your drain pan have a trap installed in the drain line? If you have no drain trap or insufficient height trap the condensate will not drain properly and will accumulate in the drain pan and some will get carried off in the airstream.

I had a commercial system in a past life with this problem and it was due to the installer thinking the drain pan was internally trapped when it really wasn't. He didn't RTFM (read the freakin manual).

[ductguy007]

The 110v wires are getting hot for some reason,pulling too many amps- Could you be smelling a real hot indoor fan motor?

[Mr HVAC41]

Originally posted by ductguy007
The 110v wires are getting hot for some reason,pulling too many amps- Could you be smelling a real hot indoor fan motor?


its kinda hard for me to put burning and musty together but i think it could be done. i imagine that your motor cooling speed winding could be going out cause you said only in cooling. i imagine also that the dust on the motor would burn. but heres my ? does the motor get really hot?

turn it off after running a cycle and feel the motor just after cycle completes. i believe they say you should be able to firmly place your hand on the motor for about 5 seconds at minimum???

[kahunabear]

Kevin,

I have the same problem with a Trame HVAC system. I would be interested in comparing notes.

We installed a high efficiency variable speed Trane heater unit with a Trane coil two years ago. We even replaced all the duct board with black antimicrobial board. When we first turn the AC on in the spring it smells terrible like dirty socks.

Our old unit was a much less expensive low efficiency unit and never had the problem. As long as we are switching back and forth between heat and AC we have the problem. Once we go to AC only, the coil seems to clean itself and the problem goes away.

Based on my reading, I think the problem may be caused because the heater doesn't get hot enough.

If not that, perhaps it is something with the coil. It is a V shaped coil. The old one was flat.

We use pleated filters and I am absolutely certain the current system has nowhere near the contamination that the old one did.

[atphvac]

I had a similar problem with one of our replacements and it drove me nuts. First my installers didn't put a trap because they said the drain line was going down into the water in the sump pit. I found the line stubbed into the top. Well the new unit apparrently creates MUCH more condensate than the old system and was raising the water level in the sump pit and pushing the odor of the stagnant water back through condensate drain and into the air stream. The sump pit must have drained at a higher rate than the old system could fill it so the water level in the pit used to remain constant. We put the line down into the water and also added a trap and the problem went away.

[nmujjohn]

ODORIFEROUS COILS

ODORIFEROUS COILS
At one time or another, everyone in the industry has come into contact with an odoriferous air conditioning or heat pump evaporate coil. While not a significant problem in terms of shear numbers, any coil odor can be a baffling problem. In our customer’s eyes, the unit is the problem, not the environment in which it operates. In the following report, we will deal with the cause(s) of an odoriferous coil and the methods which can be used to resolve/control the problem.
Some of the first published accounts of unusual coil odors emanating from air conditioning equipment first appeared in the late 1950's. Since that time, reports of odoriferous emissions have steadily increased. Odoriferous coil reports have gone from a problem confined primarily to large office buildings to the home environment. The acceptance of air conditioning in our daily lives as well as new construction techniques have increased the prevalence of air conditioning odor. The introduction of new materials coupled with the increased emphasis on building tightness has contributed to the rise in coil odor problem. While research continues in the area of coil odor, it has been directed more toward the health hazard involved and not the cause and control of coil odors. Odor perception in humans is a very complex process. By definition, our sense of odor perception results from a unique combination of nerve impulses sent by odor receptors located on the lining of the nose to the brain. In the process which takes place, the presence or lack of moisture can greatly alter the perception of odor. The addition of only modest amounts of moisture to most substances significantly increases their functional odor. For this reason, coil odors appear to be intensified just after condensation starts to take place e.g., start of a cooling ON cycle or just after a heat pump goes into defrost. We can adjust to many strong odors by the involuntary process called “Odor Blocking”.
In this process, odor signals sent to the brain are ignored, resulting in no odor being perceived. Classic examples include: persons who live in the area of a chemical processing plant or the persons who work there after a period of time not noticing the odor(,s). However, persons when confronted with the same odor, which has been concentrated, may find the odor to be quite objectionable.
Three distinct odor groupings can be identified as the primary sources of coil odors.

These groupings are represented by: (1) MOLDS, FUNGI AND YEASTS, (2) COMMON HOUSEHOLD ODORS, and (3) ORGANIC CHEMICALS. While the three groupings can be helpful in the determination of an odor source, it must be remembered most coil odors are complex mixtures. Therefore, the compounds and substances making up a specific grouping may combine with another group to intensify or even mask the odor. Furthermore, as we discuss the odor groupings, it must be kept in mind that the presence of moisture, even in modest amounts, can significantly increase odor intensity.


MOLDS, FUNGI AND YEASTS
Our first group molds, fungi and yeasts tend to form under moderately warm, moist or stagnant conditions. The odors produced by these substances can have a strong, sharp or weak, sweet, sour or musty odor. In extreme cases a methane or sulphuric odor can also be produced. Typically most people describe these odors as that of old newspapers, rotting vegetation or animals, sulphur, natural gas or stagnant water. As molds, fungi, and yeast are one celled animals, a source of organic matter must be present for them to proliferate. Dust, lint and common soils in a moist environment can provide decaying matter needed to promote reproduction. Therefore unit filters and coil surfaces must be kept as clean as possible. Stagnant water conditions in the unit environment and the coil condensate pan must be avoided. As one might expect, the presence of a dehumidifier, may be the best clue as to the source of the odor.

COMMON HOUSEHOLD ODORS
Common household odors such as tobacco smoke, food odors, perspiration and pet odors form the second group of materials which can produce coil odor. Because these odors make up the typical background odor environment of many homes, they can be quite difficult to detect as the cause of the problem odor, unless concentrated. As the unit filters, the system insulation and home furnishings can absorb these odors, resolution of the problem may never occur, even after repeated coil washings. Besides looking for the obvious sources for the odor, the life styles of the owners and their children must be considered. Are we dealing with sports ethusisasts: runners, joggers, tennis players, golfers, softball/baseball/basketball players and the like? Is laundry equipment close to the furnace? Is there ample fresh air entering the house or is the house tight as a drum?. These factors can be major contributors to coil odor problems.

ORGANIC CHEMICALS
The materials used in home construction/remodeling and home furnishings have changed drastically in the past 10 years. This change, coupled with the increased emphasis on tight homes for energy conservation, has presented an increase in organic chemical levels in the typical home. Today, increased levels of formaldehyde, esters, ketones and aliphatic, aromatic and haolgenated hydrocarbons can be found in the home environment. These materials are commonly used to produce furniture, cabinets, flooring products, carpeting, sealants and adhesives. Vapors from these compounds can be generally identified as producing odors which are: light to heavy, sweet, irritating to the nose and producing dryness of the throat and nose. Providing a solution to the coil odor problem is just as complex as the cause. In the vast majority of cases, the unit serves only to concentrate and recirculate the odor. For this reason, solutions to the problem are limited. Washing the coil and the replacement /cleaning the unit filters an a regular basis along with establishing condensate pan drainage are the first steps to solving any odoriferous coil problem. However, coil odors may return due to recontamination of the coil by the original organic vapors and substances. In such cases, recommendations for the addition of fresh air infiltration and more air changes would be warranted. While the life styles of the home residents can not be significantly altered, suggestions aimed at reducing household odors could be made. The use of exhausthoods during cooking, dehumidification of damp areas and not accumulating soiled laundry in the area of the unit would be suggestions which could lower the possibility of an odoriferous unit coil. As can be seen, coil odors and their perception is a very complex problem. It is hoped the foregoing information has shed new light on the subject and can be used to begin to solve the perception of a “smelly” coil.

ODOR PERCEPTION
1. A unique combination of nerve impulses sent to the brain by receptors located
in the lining of the nose.
2. The addition of only modest amounts of moisture to moist dry substances
increases their functional odor.
3. Odors can be ignored by the brain by a process known as “Blocking”.
MOLDS, FUNGI AND YEAST
1. Strong, Sharp or Weak, Sweet, Sour or Musty odor
2. Can also be similar to Natural Gas or Sulphur
3. Moist areas promote reproduction
4. Stagnant Water
COMMON HOUSEHOLD ODORS
1. Tobacco smoke
2. Cooking Odors
3. Perspiration
4. Pet Odor


ORGANIC CHEMICALS
1. Formaldehyde
2. Esters and Ketones
3. Aliphatic, Aromatic and Halogenated Hydrocarbon

ODOR CONTROL
1 . Washing of coil
2. Filter cleaning/replacement
3. Condensate drainage
4. Dehumidification
5. Modifications to life style
6. Fresh air infiltration, more air changes

CLEANING THE COIL
A preferred method is a cleaning solution of DAWN liquid dish washing soap in HOT water. Mix one (1) ounce of DAWN with one (1) quart of HOT water.
Spray down the coil and allow to soak for 10-15 min., with clean water rinse, rinse, and rinse again. Clean the coil again using a "commercial" coil cleaner. It must be for evaporator coils, the industry standard is the green color cleaner. Let the coil air dry. There are "commercial" cleaners that neutralize odors. One such brand is EXORDER. Although this will clean the coil of odor, they may return due to recontamination of the coil. The source of contamination may be hard to locate. If the source is not found the coil will need repeat cleaning as needed.

Residential Engineering

[hvac r us 2]

Dirty sock syndrome has been around forever it seems, and in all my years I think at one point or another I have tried just about every remedy known to man.

I have tried cleaning agents, pan neutralizer tablets, coated coils, better drainage, more air, adjust charge, UV lights, RFG filters…you get the picture. Most with an average success rate.

My highest success rate on severe cases has been replacing the coil with a coated coil.

I predict this problem will still be a problem 20 years from now.

If I have a sever case of dirt sock syndrome anymore I like the idea of recommending a competitors coil.

This way, if the problem goes away or not, it’s no longer my problem! LOL :) :D

[Chad711]

Seen this before, only smells when the a/c is running correct?

You need to get some baterial treatment for the coil, Ive seen it before. The smell is horrid!

Still like said it doesnt always work, might need to change the coil.

[TitleLess]

Here are soem excerpts from a good thread on the subject, basically your house is too humid when you are not running your air, you may need to invest in a better system,




This is known as the dirtysock syndrome, sometimes it comes from a unit sitting idle in humid areas and bacteria grows on the cooling coil while the unit is off, then when the unit comes on it activates the bacteria and sets off the smell that eventually goes away if left run long enough,my guess would be that the unit is off at night or somethng and the building has no good setback control or the ability for humidity to bring it out of an unocc period. The smeel is the same smell that you get out of a car AC every once in a while during humid conditions and the car has set for a while.


Here is a small article on the Dirty Sock Syndrome

(("Dirty Sock Syndrome" is caused by the growth of mold and bacteria on the indoor coil and the drain pan of the Heat Pump. All Summer long, moist cooling coils can serve as an ideal breeding ground for mold. But why is it only with Heat Pumps? ))

They refer to heatpumps here because they don't have a high heat temperture, but the reality is that it can be any cooling coil that has long off cycles, ecspecially when the off cycle is during a high humidity state.So any unit that tends to short cycle or is shutdown without the ability to come on with temp or humid request during the unoccupied cycle, has the potential to create the odor, it's not exclusive to any brand or type of metal, it's bacteria growing on the coil and in the drainpan,

So why does a cooling coil activate the bacteria ?

It's a change in temperature that it is reacting to, it could be hot or cold, as long as the hot is not hot enough to kill it before it reacts, thats why you get the smell with heatpumps going into the heatmode after a humid summer, and thats why you get it when the cooling comes on after a long off cycle.If it stays in the fan only state it doesn't change temp rapidly and does not react all at once.


You can find this thread here


http://www.hvac-talk.com/vbb/showthread.php?threadid=75170

[mackie]

Has this problem been resolved?