Combustion air damper for two furnaces and two replacement air
(One Power Close, One Power Open)
Hoyme Manufacturing Inc. Special Note: Circuits are colored for
and are not necessarily those found in actual installations.
Combustion Air Damper Wires, however, are
colored as shown.
Forced Air Furnaces having a
common combustion air supply duct and two separate replacement fresh air
1. Combustion Air Damper
but having only
combustion air supply duct. *(Damper has two separate operating
Replacement Air Damper
inter-connected to the HOM damper.
OPERATION: Combustion Air Damper is interlocked to both appliances so that the damper
proves to be open to supply fresh air for combustion when either one or the other or both furnaces are firing. HAC
Replacement Air Damper (PC) of the main furnace will open when either furnace fires but will draw in air whenever the
main furnace circulation fan is running. HAC Replacement Air damper (PO) of the second furnace will open only when the
second furnace fires and will close when the fire stops, regardless of furnace fan operation.
Optional switches, as shown, may be used on either HAC dampers to open
1222-ld - Printed in