High and low returns

Heating · Duct Systems, Registers and Grilles · printed page 130 (PDF page 131)

Book index entries

Forced Air – High and Low Returns High and Low Returns for Forced Air Systems Low and High Returns for Forced Air Systems Heating Distribution System – Forced Air

Text in the illustration

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

Generated explanation

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 lower openings. In summer cooling mode, the lower return register damper is closed, directing warm room air into the upper return grille while cool air enters through the supply register. In winter heating mode, the lower register damper is fully open and blocks the return path from the upper opening, allowing cool air near the floor to enter the return. Arrows show supply air rising and circulating across the room toward the selected return opening.

Components

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

Related illustrations

1255

High and low returns

· p. 223

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