Blue circuit board with a 3-digit LED display and several electronic components on it

Kevin Thigpen

Technical Services Manager North Alabama District

February 9, 2021

2-Stage Heat Pump Wiring

This month, I am covering a topic I have had a few calls on. 2-stage heat pump systems not cycling on until a Y2 call.


Making this correction will allow the system to operate correct and stage as needed. From the factory Wiring Diagram attached below the P1-5 Shows to be a yellow wire from the IFB for a Y1 call which will allow unit to cycle on in Low stage, and a Pink wire from the IFB to the SOL to energize the Sol for High stage. I have had a few calls from Techs were the P1-5 wire was Pink and the wires to the Sol were Yellow and Black which are not as the wiring diagram shows. The unit would only cycle on with a Y2 call due to the Y1 wire landing on the SOL.


If you correct the factory Wiring as show in wiring Diagram the unit will operate correctly as it’s designed to run. Feel free to contact your Local DSM for any questions.

Source: Wiring Diagram is from the factory Installation Book which can be downloaded RC Mobile Tech App or hvacpartners.com

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