Air Furnaces sharing a
supply duct controlled by one fresh air damper with Power Closed Damper
Hoyme Manufacturing Inc. Special Note: Circuits are colored for
and are not necessarily those found in actual
Diagram #8C: Two
Forced Air Furnaces sharing a common
supply duct controlled by one
Close fresh air damper with a
Relay. The damper opens when either furnace fires. If using a
Open damper, go to wiring
Diagram # 8C1
Replacement Air Control Damper with a relay, Power Close (HAC-0x11-OPC)
= diameter of the damper.
24Vac Relay Adaptor
to operate the damper from either furnace.
Note: The damper is a Power Close damper
type so that if either furnace fires the damper will open and remain open
until both furnaces turn off.
will allow the damper to open as required.
N.B. Replacement Air Damper is not affected by the ‘Manual’ setting of
the furnace fan or by the operation of an Air Conditioner.