Hi guys, can I revisit this question?
I am still getting odors from my heating system. The smell is of musty wet dog, old tennis shoe, dirty laundry, body odor type of smell. Thats the best way I can describe it. It is a moist smell at any rate. It does not happen all the time, but rather a few times a week and always when the heat pump has defrosted itself.
I say defrosted, but its not at all like the outside unit is caked with frost and needs defrosting. In fact I have never noticed an ice build up on my units. I can hear the pumps build up pressure, then there is a whooshing sound similar to a truck bleeding its airbrakes. It is at this point that the temp of the forced air inside my home rises by several degrees even though I know the aux heat is not engaged. It is also at this point that I get these awful stale odors.
I have shoved my vacuum hose as far as it will reach into each into each of the vents and pulled out various construction garbage like sawdust, scraps of drywall and wood, and a couple of soda cans but no laundry. The smell is always associated with the defrost cycle of the unit and always happens when the forced air is warmer and feels more humid right as the unit is defrosting.
Any help or suggestions here?