I am using a Takagi JR to heat the floor in my farm shop. The building is 4 years old as is the heater. I have had problems in the past with the unit shutting itself down. It would ignite for just a few seconds and then shut down. If the front cover was removed the heater would keep running with no problem. The first time this happened the unit was only a couple of months old. Talked with Takagi and they said the burner was sooted up which it certainly was. I cleaned it creating a considerable mess and it has run a couple of years with no problem. Just recently the problem came back. I removed the cover and everything worked fine. On a side note we have noticed a sooty dust buildup everywhere in the building and have been blaming it on everyday shop projects,etc even though we are extremely careful about running engines, blowing dust etc in the shop. There just seems to be a mysterious cause to all the dust and dirt. It covers everything. After running the Takagi for a couple of days without the cover I have noticed soot building up on the shop ceiling and in corners. I now suspect that our dirt and dust problem has been soot from the heater all along. The exhaust is nice and tight and sealed properly and there are no signs of leakage there. Does anyone know how this could be happening and why the burner should soot up? I love that little heater but am wondering if I should replace it with a boiler instead. Any tips on an easy way to clean that burner?