MRCOOL Versa Pro Wiring Guide: Power, RS485 Comms & Google Nest Thermostat Setup

In this video, I walk through the complete wiring setup for a MRCOOL Versa Pro split heat pump system, including power wiring, communication wiring, and integration with the Google Nest Learning Thermostat. You’ll see how I: Connected 18/7 thermostat wire from the Google Nest Learning Thermostat to the air handler control board Wired the 18/2 shielded RS485 communication cable between the air handler and condenser Installed 14 AWG power wiring for the air handler’s 15A 240V 2-pole circuit Installed 10/2 or 10 AWG wiring for the 30A 2-pole condenser circuit with a non-fused disconnect Ran 1/2" flexible PVC conduit to protect both power and communication wires outdoors I also show clean routing, labeling, grounding, and safety considerations. Important Note (Not in the video): If you're using a Google Nest Learning Thermostat instead of the MRCOOL proprietary thermostat, you must set Dip Switch #1 on SW1 to ON on the air handler control board. It’s OFF by default. Turning it ON allows third-party thermostats to work correctly. Why this setup works With this wiring configuration, you can control your full MRCOOL Versa Pro split heat pump system using the Google Home app, while still maintaining proper RS485 communication between the air handler and condenser.