What can cause excess soot in an oil furnace?
Regarding this, why is there black soot coming from my furnace?
Incomplete Combustion No matter where you find soot on or around your furnace, it always comes from the same place: the burners. This is called “incomplete combustion.” One of the combustion byproducts is carbon, the primary ingredient in soot, which is sent up the heat exchanger and out of the house.
Similarly, what causes a Puffback?
Puff backs occur when an oil-burning furnace doesn't ignite when it should. Oil vapors build up in the ignition chamber, causing an explosion when the igniter finally triggers. The explosion blows soot and other debris through the furnace's exhaust system and into the heating system, which carries it into the house.
Atomized Explosions Essentially, backfires occur when your oil furnace misses ignition: If the burner doesn't ignite as intended, atomized oil fumes can build up; when ignition finally occurs, the fumes typically cause a small explosion.