I have a radiator, on the same floor as the burner, but attached about 5 feet up on a wall. I noticed lately that the remaining wall above the radiator is sooty and the dimensions of the dirty part of the wall is about the same size as the radiator. What could be the problem? The burner maintenance service could not give me an answer. Hope you can.
This means that dark particles in the air are carried over the radiator many times as the air circulates to heat the room, the wall above the radiator will pick up more particles than anywhere else because the air moves over that spot more than over the wider area of the wall. The small particles concentrate at that point. This is an indicator that there are particles to deposit on the wall.
And my question would be, What are these dark particles and where are they coming from? If it is soot, that indicates a leak in the burner vent piping. If soot is leaking, then the real concern is Carbon Monoxide is leaking also. CARBON MONOXIDE KILLS!!!!!
If you don’t have a carbon monoxide detector, you need to get one and put it near the radiator soon. If it was my house, I’d be on the way to the store now, not typing on this ‘puter!