Heat pump heat smells musty

justjeepin86

justjeepin86

Well-Known Member
Joined
Jul 9, 2005
Location
Winston-Salem, NC
So, in the last couple days our heat downstairs has started smelling musty. It was fine before that. Maybe a 5 year old system. I Google searched, but that seemed to turn up problems when you first turned the heat on for the season. That's not the case here. Any suggestions?

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It could be musty underneath with all the rain as stated above, but like you said it’s a closed system. I’d crawl around and make sure everything is intact. The house I just moved into has some crusty ass ductwork underneath the house. I had to seal up some areas. Looked like somebody tried to seal it up 20 years ago with paper mache. Had to do the same in the attic.
 
Check if the any of the ducts have a belly in them.moisture can pond in a sagging duct with the a.c. and the hot air will evaporate it when the heat is switched on and stink.
 
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mommucked said:
Check if the any of the ducts have a belly in them.moisture can pond in a sagging duct with the a.c. and the hot air will evaporate it when the heat is switched on and stink.
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The only thing with that is it just started. We have had heat running for a few weeks. I'll get under and check out when I get back in town on Sunday.

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Any gas backup in that system or just a HP with electric strips? If gas, your heat exchanger is cracked and water gets into the box. If no gas backup then disregard.
 
I would look at the evaporated or indoor coil for debris or mold growth. Also if the strip heaters have mold growth theywill produce a musty odor when heated
 
moldman05 said:
I would look at the evaporated or indoor coil for debris or mold growth. Also if the strip heaters have mold growth theywill produce a musty odor when heated
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This^. Plus check the drain line for the evaporator / indoor coil. My unit is in the basement, with a sump pump for the condensation, that runs outside. I've had it just barley underground, at some bushes, to water them. Ground got so saturated, the line backed up, & was dumping the water in bottom of my unit. But, I did Not have any smell. Just water in the floor.
 
Wes said:
It could be musty underneath with all the rain as stated above, but like you said it’s a closed system. I’d crawl around and make sure everything is intact. The house I just moved into has some crusty ass ductwork underneath the house. I had to seal up some areas. Looked like somebody tried to seal it up 20 years ago with paper mache. Had to do the same in the attic.
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This is going to be the issue. You have a leak in your return air ducting somewhere and are getting crawlspace air into the house.
 
braxton357 said:
This is going to be the issue. You have a leak in your return air ducting somewhere and are getting crawlspace air into the house.
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If there isn't a continuous vapor barrier on the ground, that makes it worse.
 
So there is definitely a little water under the house from all the rain. It smells a little musty. I think I found the problem. Looks like the tape is loose around the return where it enters the system down there. It, for sure, would pull in air from the crawl space. I'll redo that and see what it gets me.

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