solid layer of fine black powder in my air ducting

[sparr]

I've recently acquired a 2003 Optima Opus LFB34 with what I think is a ThermoKing climate control unit on the roof. The air out from the roof unit goes into enclosed areas along the upper edges of the bus, running front to back, and enters the cabin from there. Those enclosed areas are also home to the electrical wiring, refrigerant hoses for the climate control, etc.

The ducts coming out of the roof unit are clean. However, *everything* inside the enclosed duct-like areas of the bus is completely covered in black powder. Could be exhaust soot, could be ground up rubber. It's dry, not oily. It's *super* fine, like talc powder. It's pitch black.

How can I tell what it is, and whether it's supposed to be there or not? (for all I know, it's an anti-corrosion coating that was intentionally put there). How should I remove it, if I should?

[Scott & Heather]

Sounds like soot buildup from a poorly running furnace.


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[buswarrior]

It doesn't belong, get it cleaned up.

Does it pick up on a rag? Do you have a good filter on your ShopVac?

You don't want to breath that crap, and you don't want to re-distribute it through out the coach with your cleaning methods.

happy coaching!
buswarrior

[sparr]

Does it pick up on a rag?

It picks up on anything. It's not adhered to the surfaces at all. Simply brushing my hand against it wipes it off almost completely, leaving my hand black.

I'm looking into how to get rid of it, given how insidious some of the crevices are.