I found this... (it may be significant - or perhaps not)
There is a black "soot" coming from my radiant heater
it goes up the walls above where the heaters are installed and on the windowes and curtains, and this "black soot" is not easy to clean or wash out of fabrics. There were new heaters when i moved into my condo 4 years ago and i am constantly repainting my walls because i cannot wash or remove this "black soot". What would cause thsi broblem
Black soot appearing above and around electric baseboard heaters is caused by burnt hydrocarbons in the air.
The Heating element draws the cool room air from the bottom and over the element. Any excess hydrocarbons in the air become burned and are deposited on the surrounding surfaces from the warm heated air flowing up out of the heater.
The Heater is not the cause of these hydrocarbons. They come from the home / enviornment.
Some cause.
Smoking, burning Candles releases waxy hydrocarbons, carpet cleaning solutions, spray type air fresheners.
Black waxy sooty deposits are usually from burning candles.
http://www.fixya.com/support/t1535561-black_soot_coming_from_radiant_heater
Peccavi
February 2010