Single-stage 24V contactor
Conventional Y / C
One cool stage. Indoor transformer, stat Y, outdoor contactor coil. Dual cap on the outdoor. No data pair and no Y2.
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.
Open manufacturer PDF24V single-stage
Plate is a one-contactor condensing unit.
Wall thermostat
Conventional 24V. One cool stage.
- R24V hot from indoor transformer24V
- C24V common24V
- YCool call — one stage24V
- GIndoor fan24V
- WHeat. Stays at the indoor.24V
Indoor IFC / AHU
Y in from the stat. Y out to the outdoor contactor. Same transformer.
- RTransformer hot — feeds the stat24V
- CTransformer common — must reach the outdoor24V
- YStat Y in24V
- YoutTo outdoor contactor coil24V
- GBlower / cool tap24V
- WHeat only24V
Outdoor — contactor coil
Two control screws. There is no outdoor IFC to interrogate.
- YContactor coil. ~24 VAC to C under a call.24V
- CContactor coil common24V
Outdoor line
208/230 through the disconnect to the contactor line side.
- L1LineLine
- L2LineLine
- GNDEquipment groundLine
Dual run capacitor
C / FAN / HERM on the can. An inverter outdoor does not have this part.
- CCommon — both windingsCap
- FANOutdoor fanCap
- HERMCompressorCap
Landing
- 24VIndoor Rstat R
~24 VAC hot
- 24VIndoor Cstat Coutdoor C
Common. Outdoor will not pull without it.
- 24VStat Yindoor Youtdoor Y
~24 VAC across Y–C at the contactor under a call
- 24VStat Gindoor G
Indoor blower. Does not go outdoors.
- LineL1 / L2disconnectcontactor line
208/230
- CapCap C / FAN / HERM
Both sections vs the can stamp
Prove it
- 24 VAC across outdoor Y and C under a Y call, measured at the outdoor.
- Contactor pulls and stays. Chatter is low 24V, a cooked coil, or HPS in series.
- Dual-cap FAN and HERM both in spec.
Do not
- Do not land a ComfortBridge / ABCD / iComfort data pair on this outdoor. It wants Y and C.
- There is no O/B. That screw is the heat-pump twin.
- There is no Y2.
Field landing, not a scanned OEM schematic. Photograph the outdoor silk if the screws are not labeled Y/C.