Anybody ever heard of it?
I have 5 seperate air handlers with hot and cold water coils. The coils (and control components) are about 10 years new, the rest of the system is almost 50 years. About 2 years ago, one of my buildings began reporting a "musty" odor......but sporadically and not constantly. Sometimes in the morning, sometimes in the afternoon, sometimes strong, sometimes not.
The only factual correlation I can draw is that it always happens while the chillers are running.
Does not happen at all during the heating season. (this interests me, because in my limited knowledge of biology, HEAT tends to activate bacteria or mold spores, not COLD!)
So, we began inspecting. We took tape samples from all surfaces for our risk mgmnt folks to assess. (all negative other than common mold spores, and not in any quantity which would cause problems, according to the industrial hygienist. The inside surfaces (lagging) were pretty dirty, especially just after the coils, so we removed it. We steam cleaned the coils from both directions. We used several coil cleaning solutions, per directions, then steam cleaned again. This would cause abatement of symptoms.....sometimes for as long as 3 or 4 months.
(BTW, we do treat our condensate pans properly.......kind of rules the pans out as a source......I THINK!)
Now, last week, a different building is experiencing the same problem. Same smell. What is strange is that the smell seems to come in "waves", meaning it will present itself for a few minutes, or an hour, and then disappear.....with no rhyme or reason that I can tell.
What a great wealth of knowledge here on HVAC.com, Im hoping maybe some of you will point me in the right direction. I appreciate your taking the time to read this.........
signed, a frustrated operating engineer.