HP in marine environment / dirty sock smell

[soundbalance]

A customer of ours has an issue in San Diego with some of their heat pumps. They get a reoccuring musty smell from time to time, usually around transition time from heat to cool. They have tried all of the traditional cures (coil cleaning, UV lights) with some success, but it has always been temporary. Have you seen this before, and do you have any ideas on how to cure it? The units have been gone through carefully, so it is not an easy fix like a plugged condensate line. It is also a wide spread issue.

[JRINJAX]

A customer of ours has an issue in San Diego with some of their heat pumps. They get a reoccuring musty smell from time to time, usually around transition time from heat to cool. They have tried all of the traditional cures (coil cleaning, UV lights) with some success, but it has always been temporary. Have you seen this before, and do you have any ideas on how to cure it? The units have been gone through carefully, so it is not an easy fix like a plugged condensate line. It is also a wide spread issue.

First;The name of the problem is "dirty socks syndrome" and it is caused by a common, harmless/inert mold that grows in the wet crevices of the cooling coil. It dies when the coil dries out and remains inert, but when the coil gets wet, during cooling or defrost, it releases a terrible smell.

We use a micro-encapsulated chlorine dioxide such as Ace's Ecotreat for temporary relief. There is no permenant fix....

[dapper]

JRINJAX, you nailed it! The name is very appropriate. I had a similar problem for many years in a TV studio. We did everything from power washing the inside of the unit to treating with bactericides and chlorine bleach. Each time the fix was temporary, sometimes returning the next day. The odor was only present when the unit ran in the cooling mode. Eventually the whole unit was replaced to cure the problem.

[megohm]

Trane units I used to service years ago had the same problem when the mold would begin to die in the heating season then trane came out with a new evap coil that came pre-treated with a anti bacteria coating they would actually exchange the coils for new ones if under warranty.

[dapper]

The unit that I had a problem with happened to be a Trane. It was pretty old at the time it developed the problem.