puffback

noun

1. Any bird of the genus Dryoscopus.
2. The (unintended) emission of soot or smoke from a furnace or boiler into a structure, typically caused by a burner failing to ignite properly, allowing a buildup of fumes which explode and expel soot or smoke into the structure.

   “Puffback can also be caused by a faulty pressure regulator that allows oil to drip into the combustion chamber after the burner shuts down. The leaking oil gets absorbed by the lining of the combustion chamber, and it can also pool[…]”

   “Broken or malfunctioning electrodes can result in smoke leaking out into the rooms of the structure. This problem, called a puffback, is not an uncommon one in oil-fired appliances (see sidebar).”

   “Oil burner smoke from a puffback is usually cool and easy to breathe. Self-contained breathing apparatus (SCBA) is not needed. High heat emanating from the oil burner room, accompanied by thick black smoke, is an indication of a [puffback].”