Packaged rooftop · heat pump 24V
R / C / Y1 / O-B / W-aux / G
Written landings stay open. Diagnose is the seat.
Packaged heat pump. RV is in this cabinet. Electric heat is aux. Economizer still steals the cool call on mild OA.
Written circuit description only — FieldBench does not redraw maker schematics. Example: R to W closes on a heat call; verify 24V at W1 before you change the IFC. Packaged: Y1 may go to the economizer, not the contactor; VFD enable is 24V, speed is 0–10 V.
Open manufacturer wiring diagramCabinet sequence
- 1Power. Disconnect → transformer → RLine / 24V
- 2Fan. G → indoor blowerProve before defrost heat
- 3Cool/HP. Y1 → contactor; O/B → RV~24 VAC
- 4Aux. W → stripsElectric heat
24V packaged HP
Plate is 50FCQ / WSC / GPH / ZH class — no gas valve.
Thermostat / DDC
O/B is the RV. W is electric heat / defrost aux, not a gas valve.
- R24V hot24V
- CCommon24V
- Y1Compressor24V
- O/BReversing valve — confirm this controller’s silk24V
- WElectric heat / aux24V
- GIndoor fan24V
Unit controller
Defrost, economizer, and the RV relay live here.
- Y outContactor through HPS24V
- RVReversing-valve solenoid24V
- AUXElectric heat24V
- EN / 0–10Indoor VFD enable and speed, when this cabinet is a drive24V
Economizer
Still steals the cool call on mild OA. Same FDD sensors as the G/E cabinet.
- ACTActuator 2–10 V or 24 V floating24V
- OA TOutside-air sensor24V
- MATMixed-air sensor24V
Landing
- 24VY1contactor through HPS
Compressor
- 24VO/BRV solenoid
Shift. No shift is not a charge call.
- 24VWelectric heat kit
Aux / defrost
Prove it
- Y1 at the board.
- O/B present on the call this silk uses.
- Damper not stealing cool.
Do not
- Do not look for an IGC on a 50FC / WSC / GPH.
- Do not diagnose defrost with a split-system defrost board chart.
RV is in the packaged box. There is no outdoor unit on the ground.