Related illustrations

0716.3

Conventional gas furnace

· p. 113

A cutaway illustration shows a conventional gas-fired forced-air furnace with a labeled seasonal efficiency of 60%. Cold return air passes through an air filter or air cleaner into the lower circulating-fan compartment,

0716.9

High efficiency gas furnace

· p. 113

A cutaway diagram shows a high-efficiency gas furnace with a lower house-air blower and filter, primary and secondary heat exchangers, and an upper warm-air supply duct. Dashed duct outlines and colored arrows indicate c

0716.6

Mid-efficiency gas furnace

· p. 113

A cutaway illustration shows a mid-efficiency gas furnace labeled with a seasonal efficiency of 80%. Cold return air enters through the side-mounted filter or air cleaner, and a circulating fan in the lower compartment m

0756

Furnace covers

· p. 123

The illustration shows an upright gas furnace with separate front covers for the burner and fan compartments. Arrows identify the upper burner cover and lower fan compartment cover. A cutaway at the lower left reveals th

0754

Horizontal gas-fired furnace

· p. 122

The illustration shows a horizontal gas-fired furnace installed beneath wood framing in a space with limited headroom. Return air enters from the left through an air filter and is moved by the blower toward the heat exch

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

0809

Pulse furnace - how it works

· p. 134

Four schematic stages show the operating cycle of a pulse gas furnace, with a combustion chamber connected to a long, looping tailpipe. In stage A, air and gas enter through flapper valves near the spark-plug igniter at

0755

Fan cover missing

· p. 123

The illustration shows a forced-air furnace with its lower fan compartment cover missing, exposing the blower. Dashed outlines identify the cold-air return and supply plenum, and an air filter is shown beside the blower