musty odor from a/c vent

[Clifftall]

At start up and only for a few seconds I'm getting a slight musty odor from the inside ceiling vents. My filters are clean and get changed every two weeks. The fins on the roof unit look pretty clean. We've had a lot of rain lately and we are in cooler temps and the air only comes on a few times a day. Any thoughts?

[powerboatr]

high humidity for one
and the a/c is shutting down and then the moisture on the evap, drains off and some stays behind and causes mold. add in the grime and gunk that builds up in the vents and on the evap coils

if your in a high humidity area, put the a/c fan to ON and let the compressor cycle as needed, this will continue to move air will help with the odor


also since its summer, the whole unit should get a good cleaning
remove the roof cover and clean the condenser coils and fan blades

on my unit the roof side provides superb access to the evap coil. the cover unscrews and gives you 100% access to clean the coils and blower fan.

[ralper]

The condensate drain pan probably needs cleaning and maybe the evaporator coil too. That is the cooling coil the indoor air passes over.

[paz]

Quote:

Originally Posted by ralper The condensate drain pan probably needs cleaning and maybe the evaporator coil too. That is the cooling coil the indoor air passes over.

That sounds like what the problem is to me, too. Climb up on the roof, take off the outside cover, and check the drain pan and coils for blockages, debris, wasp nests, or anything that can trap moisture.

[TXiceman]

You need to check the evaporator coil for any dirt and mold build up. Make sure the interior of the air side is clean. try a weak chlorine bleach wash down on the inside of the unit. But you will need to be very careful to not get the bleach on furniture, carpet of clothing.

Ken

["007"]

This is what you may find when you remove covers for AC.



This link will show what you need to do.

[Clifftall]

Quote:

Originally Posted by "007" This is what you may find when you remove covers for AC. This link will show what you need to do.

Thanks Roger and all that responded. I used to have basement air but now I know that this process needs to be done to my roof units.

[Clifftall]

I bought a spray foam coil cleaner. It says you don't have to rinse. The foam will break down and the condensation will do the rinsing. I wonder if this will clog up the drain holes as it flushes out the dirt and grime. Anybody have experience with a product like this? Thanks Cliff

[Clifftall]

Quote:

Originally Posted by clifftall I bought a spray foam coil cleaner. It says you don't have to rinse. The foam will break down and the condensation will do the rinsing. I wonder if this will clog up the drain holes as it flushes out the dirt and grime. Anybody have experience with a product like this? Thanks Cliff

Here is a photo of the product.

[FreeByrd]

We had the same issue last summer in FL and NC. Found that if we moved the Thermostat Fan to ON from AUTO during the more humid & warmer daylight hours (while the AC did most of it's cycling) and then switched it back to AUTO at night that it kept the vents that distribute the cold air from building up a lot of condensation. We also occasionally spray a little Lysol from time to time into the intake vents (filters removed) and that doesn't seem to hurt either.

[Clifftall]

Update. After cleaning the coils three times they looked like new but still had the musty odor at start up. The forth time was the charm as I noticed the thin insulation on the inside sheet metal was black and smelled musty. The first owner obviously did not maintain the filters and this created this mess. I clean mine every 7-10 days. Anyway, I called RV Products and they are sending me new sheet metal for both units as they come with the insulation attached. In the meantime , I took off the sheet metal and washed the insulation as best as I could and sprayed lysol on them after they dried. This took care of the musty odor , but I still will get the new ones on when they get here.

The guy at RV Products was very helpful as they have been in past dealings.