Evaporator coil compartment...mold...HELP!

I have a new home that developed “dirty sock syndrome” in the evaporator coil unit. Mold was growing on the back of the access door and the coil stunk like crazy. Because the home was new (and the unit new) we insisted the whole unit be replaced. Now…less than a year later, we just found mold growing on the insulation of the access panel door…just like last time. This is a clean, non-smoking, no pets home. Everything is new and should be working properly. The last time this happened we found that the condensate line inside the return air compartment apparently came unglued and was disconnected. This has been repaired. Other than that, I see no reason for this dirty sock thing and mold growth. Please…any ideas???

You wouldnt happen to to have a humidifier in the system would you?
Or is the coil over hanging the blower . Meaning extended the lower unit , Possibility of the coil having dead air space.

Where is the unit located? Attic maybe? Where are you from?

Need to know your location to better answer your question.

Replacing the evaporate or coil was probably a total waste of time and money.

The evaporating unit produces water. Why is anyone concerned about humidity? That’s what the machine is designed to remove.

You must look to the source (not the HAVC unit which is the result of contamination). Your house is infected! You must locate the source and cause of this mold infestation and make changes to eliminate it.

We need a whole lot more information about this situation and will not solve your problems on a message board.

My recommendation is that you stand at the HAVC unit unit and turn around and begin looking for the problem in this direction.

The HVAC unit could very likely be causing your mold infestation due to improper air balancing in the house. Air duct leaks may cause air from contaminated exterior locations to be drawn into the house. It does not necessarily have to be inside your house.

The HVAC unit is basically a filter of all the air in your house. Because of the work that it does, it becomes a petri dish and the contaminants from all the air in your house gets passed through this media. Due to temperature and humidity conditions, this is where we will find it growing the fastest.

All…thanks so much for taking the time to reply to my question. First of all…I am baffled about why the forum says I’m a non-member. I’m a new member who joined in August…have a password and everything. If I’m doing something wrong with posting, please explain.

Anyway, back to my unit. It’s a new Lennox unit in a new home. I only lived in the house (in Austin Texas) a few months when I noticed this issue. The unit is located in a hallway just off the kitchen area. It is also directly across from the hall bath and near the laundry room as well. There are two return air grills under the unit in the hallway. The first sign of trouble was a bad smell when the unit came on in the winter. Soon after, was when the coil had to be removed and we discovered mold on the insulation of the door covering the unit. Because of my wife’s asthma, we insisted that the builder replace the unit (which they did). We thought all was well until we decided to just check the unit out again. Lo, and behold…mold
growth on the insulation again in a wide area. The builder now does not want to test the type of mold…just wants to replace the door and forget about it, but something is causing this problem and needs to be fixed.

To Wayne - No, there is no humidifier and the coil doesn’t appear to have dead air space.

I really appreciate any and all input!


Also if you did not replace the insulation inside the furnace, especially around the coil, the mold will just grow back. Kinda like mold on carpeting, drywall or any other porous material, you got to replace the material that contained the mold growth. Also the entire furnace needs to be cleaned including ductwork. Air testing will determine how bad your spore drift is now throughout your home.

The reason i mentioned the humidifier was a source for mold . As David said it may be the unit needs to be balanced . check for air leaks.

I would call a good A/C company out and have them double check the install. Make sure it’s draining properly and that balance is right and the system isn’t to big or over charged. It could be freezing up the evaporator. Does it short cycle at all? Check that your registers are open and lots of doors aren’t kept closed. Once you figure it out get the ducts cleaned. Some cleaning companies can run a mold killer while they are cleaning. My friend had a problem very close to this and it took some good investigating to figure it out.

I would reccomend doing a mold test (to be sure it is not just typical mildew). In the old days, in my commercial Facility Engineering days, we would add diluted bleach to the condensate pans. There are safer alternatives that can be purchased (Grainger) that can be added and are safe for the metals and the occupants of the home.

For mold to grow, it needs organic material and the insulation or paper over it must be that. Change the insulation/paper and then find the source of spores, if possible, though they typically are found mostly everywhere. You might as well put in a better house air filtration system, if your wife is asthmatic, while you are at it.

If your wife is asthmatic, you may want to increase her life insurance policy and start harboring mold colonies in numerous discreet locations throughout the home.

I think we coined the term “Dirty Sock syndrome” back in my frat boy days… Good one…

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1800 Camden Rd Suite 1071
Charlotte NC 28203

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Here are two links for good information.

Seal the insulation and all porous surfaces inside air handler and return air chases/ducts with anti microbial mastic. Your filtration should be a minimum of two stage with your wife’s asthma. A pleated pre filter and a large (6") cartridge HEPA filter at the intake of the air handler. A UV light installed in air stream intake prior to coil can help to eliminate airborne spores and destroy bacteria on surfaces. Depending on the the materials and configuration in your coil, air handler and drain pans, An Ultra Violet light could possibily be installed with emission directly onto coil surface.

I am 35 miles from you and was master licensed in the HVAC business for 30 years. I am also certified by Honeywell in Indoor Air Quality diagnostics.

Send me a PM if you would like to talk more or call me

This was posted on November 02, 2010!!!

I would think that the issue has been resolved!:wink: