The other day, I turned on my central air for the first time in two months and I immediately noticed an overwhelming odor that smelled like musty garbage. I had been using my central heating for two months prior to this and never smelled this odor. Nor did I smell it last summer when I was constantly running the a/c. When I have been running the heat or fan only, I do not smell the odor. It only starts when the a/c is switched on. I live in the Florida area.
I had a tech check the evaporator coils and from the front view, they appeared clean and mold/gunk-free. The drip pan was dry but he did notice a generous collection of an oily type substance in the corner of the pan. He said it had an odd smell and then cleaned it up. He checked the attic for the odor had described and carefully inspected the duct work. He didn't find anything unusual and suggested that maybe I should get the ducts cleaned...
The A/C unit is about 7 years old and in excellent shape I've been told. The coils have some rust on them however. The A/C system is very efficient so I do not believe that I have a Freon leak. I also have the unit maintained regularly. Because the odor is not present when the fan only or heat have been running, I don't believe that it is a problem with mold or dust in the ducts. The air handler is located in the garage. The garage area is odor-free. I had the attic inspected for rodents and nothing was found.
So, I am at a complete loss. Other than having the evaporator coil unit pulled and cleaned, does anyone have any other theories on what might be going on here? I am scared to use the A/C now...
Thank you so much!
Stinky in Sarasota