Home Support Colored Wiring Diagrams #8B - #8D2 #8C4

Colored Wiring Diagram #8C4

Two Forced Air Furnaces sharing a replacement air supply duct controlled by one fresh air damper with Power Open Damper
HMI Hoyme Manufacturing Inc. Special Note: Circuits are colored for clarification only and are not necessarily those found in actual installations.
Diagram #8C4: Two Forced Air Furnaces sharing a common replacement air supply duct controlled by one Power Open fresh air damper. The damper opens when either furnace fires. If using a Power Close damper, go to wiring Diagram #8C for details.

1. Replacement Air Control Damper, Power Open (HAC-0x10-OPO) where ‘x’ = diameter  of the damper.
2. 24Vac Relay Adaptor (ADP-0241-05A) to operate the damper from either furnace.
3. Ready mounted Optional Toggle Switch with Timer (SPDT) (TMADP-0240-3WS) to override the damper to be opened or closed at pre-determined times.

1. The Power Open (PO) Replacement Air Control Damper will open when the thermostat of either furnace asks for heat, and will remain open until both thermostats turn the furnaces off.
2. The ADP-0241-05A uses both sides of the relay to control the 24Vac circuits and damper.
3. The Timer/Adaptor TMADP-0240-3WS has a manual toggle switch to keep the fresh air damper open when desired but also has a 24hr. Timer that automatically prevents the Damper from opening at predetermined times due to intervals of outside foul air.

N.B. Replacement Air Damper is not affected by the ‘Manual’ setting of the furnace fan or by the operation of an Air Conditioner.

Last Updated (Tuesday, 20 October 2015 15:15)