I live in a 1989 manufactured home. The furnace (gas, forced air) is the original unit. I have been pretty good about cleaning the filter regularly (it's a reusable allergy filter) - it's been dirty before, but this time it was completely black. We've been tackling a pilot light issue for years - whenever it's windy outside, the pilot blows out. So I've had the front covers off about once or twice a week over the last month and the filter wasn't black at all the last time I had it off. (Before you chime in on this problem, let me just say we've had several different HVAC contractors out to look at it. One of them installed the "fix" recommended by Coleman, but no luck. But - - that's another thread.)

I don't know if this is relevant, but I discovered a rotted section of siding two weeks ago - roughly a 4' x 4' area of pressboard siding, also carpet and drywall and in between needs to be replaced. The affected padding and drywall has been removed. A fan was used to dry the area and we're about to start the repairs.

Someoone suggested it may be black mold on the furnace filter. Does anyone know if this is a possibility? Or what else may be the problem causing the sudden black sooty mess in my furnace filter?

Thanks very much,