Backdrafting

Heating · Combustion Air · printed page 117 (PDF page 118)

Original page Sign in to save

Book index entries

Backdrafting for Gas Appliances

Text in the illustration

if there is insufficient air available to the furnace, backdrafting can occur
check for it at the draft hood - with a match, etc., or just check for excess heat in the area
rust may also indicate a backdrafting problem
supply plenum
vent connector
cold air return
draft hood
look for rust around the draft hood due to backdrafting
smoke test
combustion products
gas furnace
air filter

Generated explanation

The illustration shows a gas furnace with a draft hood, an upward-curving vent connector, and dashed outlines of the supply plenum and cold air return. The open front exposes the burner assembly and gas controls, while an air filter is shown at the return side. A large arrow depicts combustion products spilling out through the draft hood rather than exhausting through the vent connector. Annotations identify insufficient air as a cause of backdrafting and indicate rust and excess heat around the draft hood as possible warning signs. A smoke test is illustrated beside the draft hood to check draft direction.

Related illustrations

0736

Backdrafting

· p. 118

The illustration depicts a gas furnace with a draft hood, vent connector, gas piping and burners, supply plenum, and cold air return with an air filter. A large arrow shows combustion products spilling outward from the d

0774

Backdrafting

· p. 126

The illustration depicts a gas furnace with an exposed burner compartment, draft hood, and vent connector rising from the top. Dashed outlines indicate the supply plenum and cold air return, with an air filter at the ret

0796

Return grille in furnace room

· p. 131

The illustration shows a gas furnace beside a cold-air return duct with a return grille opening into the furnace room. A red prohibition symbol marks the grille as improper. The furnace has an exposed burner assembly, a

0801

Blockage switches

· p. 132

The illustration shows a cutaway gas furnace and a schematic gas boiler, with blockage-switch locations highlighted by dashed circles and arrows. Each switch is positioned below the draft hood area. The furnace view expo