High and low returns

Air Conditioning and Heat Pumps · Duct System · printed page 223 (PDF page 224)

Book index entries

High and Low Returns Return Air Grille – High and Low for Air Conditioning Duct System Ducts – System for Air Conditioning

Text in the illustration

upper return grille upper return grille blocked by open lower register
summer
(cooling mode)
typical room
warm air
upper return grille
air flow
return
window
return register (closed)
cool air
supply register
supply
winter
(heating mode)
upper return grille blocked by open lower register
return register (fully open)
hot air
cross section

Generated explanation

Two room cross sections illustrate seasonal operation of high and low return-air openings connected to a common return duct. In summer cooling mode, the lower return register is closed, and warm room air enters the upper return grille while cool air enters through a floor supply register near the window. In winter heating mode, the lower return register is fully open, blocking the path to the upper return grille and drawing cooler air from near floor level. Arrows show heated supply air rising beside the window and circulating across the room before descending toward the low return.

Components

upper return-air grille lower return-air register return-air duct floor supply register supply-air duct window room walls floor ceiling

Related illustrations

0792

High and low returns

· p. 130

Two room cross sections illustrate seasonal operation of high and low returns in a forced-air distribution system. Both show a floor supply register beneath a window and a return duct on the opposite wall with upper and