Conventional gas furnace

Heating · Gas Piping and Meters · printed page 113 (PDF page 114)

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Furnace – Conventional

Text in the illustration

warm air supply duct
heat exchanger above burner
cold air return duct
gas pipe with sediment trap (drip leg)
air filter and/or air cleaner
seasonal efficiency: 60%
metal vent connector (to chimney)
draft hood
fan limit switch
gas valve
heat shield
burner
pilot light
combustion air
circulating fan

Generated explanation

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, and heated air exits through the warm-air supply duct above the heat exchanger. The burner and pilot light sit below the heat exchanger, with a gas valve, heat shield, and fan limit switch identified. An external gas pipe includes a sediment trap (drip leg), while a draft hood and metal vent connector provide a path toward the chimney. A separate arrow indicates combustion air entering the furnace; no defects are identified.

Components

gas furnace warm air supply duct cold air return duct heat exchanger gas pipe sediment trap air filter or air cleaner metal vent connector draft hood fan limit switch gas valve heat shield burner pilot light circulating fan furnace cabinet

Materials

sheet metal metal piping