Gravity furnace

Heating · Combination Furnaces · printed page 136 (PDF page 137)

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Text in the illustration

heat registers are on inside walls
second floor
usually only one cold air return (on the main floor) and it is often located near an outside wall
several registers are often fed off one duct
first floor
air return
basement
supply ducts have exaggerated upward slope and are large and round
supply duct
furnace is centrally located
no fan and no filter
cross section

Generated explanation

A house cross section shows a centrally located gravity furnace in the basement serving two floors. A large return duct descends from a first-floor air return near an outside wall to the base of the furnace. A supply duct slopes upward from the furnace and rises through an interior wall, feeding heat registers on both floors; red arrows indicate warm air discharge. Annotations identify large, round, upward-sloping supply ducts and the absence of a fan and filter. The illustration presents the typical layout of a gravity warm-air heating system rather than a defect.

Components

gravity furnace cold-air return duct air return opening warm-air supply duct heat registers interior wall floor assemblies basement foundation walls

Materials

sheet metal ductwork concrete foundation walls

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