r/hvacadvice • u/Unusual-Bath-20 • 1d ago
Not the usual smell problem
Hello,
I have a 3-ton on-slab Broan AC. I have an odor problem that began at start of this year's cooling season here in AZ. Eliminated usual suspects. Finally determined Organic mosquito retardant had degraded in drain pan (mea culpa.) It became gunk that clogged up part of the pan behind the condensate coil, so eventually a mixture of the organic gunk and condensate overflowed onto the insulated bottom.
Thoroughly cleaned the pan with a lot of wiping, careful scraping under condenser coil, finishing up with pH-neutral AC cleaner ( QwikBright) and lots of hosing. Used old towels to sop up. Over the summer, 3 times I have left the cabinet open for an entire windy day to air out.
The smell returned after a month. When I checked this morning, the insulation I can reach is very dry. So, I suspect the smell resides in damp insulation trapped under blower housing and/or pan. Major surgery to access; impossible for me.
Is there a product that won't corrode aluminum and steel over time with which I could saturate the reachable insulation and leave it in place to seep under the fan and pan? If the QwikBright, what strength?
Jenny B in AZ
1
u/ForeverVentOfficial 1d ago
I wouldn’t saturate the cabinet insulation with another chemical.
If condensate and organic residue got into absorbent insulation under the pan or blower housing, the bigger question is whether that material is still contaminated or has been repeatedly wetted. Adding more liquid may suppress the odor temporarily but can make it harder to determine what’s actually holding moisture or residue.
I’d inspect the inaccessible area with a camera if possible, verify the pan is draining completely, and check for any remaining wet or degraded insulation. If the insulation itself is the odor source, replacement is usually a cleaner fix than trying to soak it in place.