"Dirty Sock Syndrome"

[reeferrat]

Tomorrow, I'm going to one of my commercial accounts (in a mall) for complaints of a gym smell coming from a particular unit. It's a larger Trane split system with a DX coil and economizer. It also has an electric heat coil (hardly gets used because of the year round natural load of the store) but it's the last component in the supply airstream. This last summer, I was dealing with humidity issues in the store which ended up being the mall's horrible lack of humidity control and I've had the account for 5 years since the store opened and there has never been humidity issues. I've read a handful of articles about the phenomenon and have read a few forum posts here. I read that condensate lines / traps / pans, leaking return air ducts and wet insulation can produce the same type of smells.

I'm wondering if anyone has found or came across anything else that has produced these smells? I would like to cover every angle and possibility before telling them it's the evaporator coil



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[shellkamp]

I wouldn't rule it out completely, but from what I understand DSS only affected "A" coils that were also heat pumps.

Trane Odyssey units use slant coils and yours is a straight cool so that should preclude DSS.

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[reeferrat]

I wouldn't rule it out completely, but from what I understand DSS only affected "A" coils that were also heat pumps.

Trane Odyssey units use slant coils and yours is a straight cool so that should preclude DSS.

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I read that it's mostly found in residential heat pumps that were in high humidity southern states, but were starting to see it commercially as well. Preclude is a very strong word my friend!! I'll post an update tomorrow after the call


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[reeferrat]

Alright so the smell wasn't present today since it comes and goes randomly. I checked everything to do with the condensate, inspected the duct insulation, unit components and outside air intakes but nothing was out of the ordinary. Also put the unit's into heating and cooling and didn't smell anything

[1manarmy]

I have occasionally had a random odor no one could find and found out that the AHU was pulling sewer smell from a dry P-Trap in the floor. The drains were seldom used so the maintenance guy was then required to add water every once and awhile.
Might not be the source of your problem but it might be at some point.

[shellkamp]

Does the customer run the fan 24/7?

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[reeferrat]

Does the customer run the fan 24/7?

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Yes


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[reeferrat]

I have occasionally had a random odor no one could find and found out that the AHU was pulling sewer smell from a dry P-Trap in the floor. The drains were seldom used so the maintenance guy was then required to add water every once and awhile.
Might not be the source of your problem but it might be at some point.

I added water to the floor drains in both bathrooms and the janitor's closet today as well. Now we play the waiting game


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[shellkamp]

Yes


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I'll bet that's the reason.

It's probably happening after nice long cooling sessions where the coil is saturated with moisture, then either the load drops off for a while or maybe they program a higher temperature setting and the fan just evaporates the water off the coil, rinse and repeat.



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[hepservice]

My experience yes, comes from ductless only but I feel for you. This is one of my most dreaded calls. Over the years I've even had it from my units at home so I'm a believer. Weird thing is it went away just as fast as it came. A coil cleaning with evap cleaner was what we'd prescribe. Most of the time I think the smell just dissipated on it's own. We had a few cases where, after a standard cleaning it didn't go away. On those we bought a special purpose mold/mildew cleaner. A spray on Pre-Clean then the final soak with the killer stuff. I think we used this 3 times. 1st the house was sold right after, so I got no direct feedback. The other 2 times I didn't hear back so..... I imagine more customers get it periodically, it goes away, and they figure, like I did, it's gone now, good. If I didn't experience the coming and going of it on it's own I wouldn't believe it. Over the last 15 years we have put thousands of heads in but the percentage of annual complaints stays relatively low. Thankful not to have ever had a complaint from a commercial account, knock wood.

[reeferrat]

My experience yes, comes from ductless only but I feel for you. This is one of my most dreaded calls. Over the years I've even had it from my units at home so I'm a believer. Weird thing is it went away just as fast as it came. A coil cleaning with evap cleaner was what we'd prescribe. Most of the time I think the smell just dissipated on it's own. We had a few cases where, after a standard cleaning it didn't go away. On those we bought a special purpose mold/mildew cleaner. A spray on Pre-Clean then the final soak with the killer stuff. I think we used this 3 times. 1st the house was sold right after, so I got no direct feedback. The other 2 times I didn't hear back so..... I imagine more customers get it periodically, it goes away, and they figure, like I did, it's gone now, good. If I didn't experience the coming and going of it on it's own I wouldn't believe it. Over the last 15 years we have put thousands of heads in but the percentage of annual complaints stays relatively low. Thankful not to have ever had a complaint from a commercial account, knock wood.

Thank you for the response! Until I smell it myself and find the source I'm not sure what to think. This was just the closest thing I could find from what the customer was describing


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