Wiring Scenarios for the MRCOOL Versapro

When wiring your MRCOOL Versa Pro there are several wiring scenarios you can use based on the specific model of your system. This guide covers three common wiring scenarios, ensuring a smooth setup whether you're using the default two-wire communication system or converting to a full 24V setup.

Scenario 1: Default 2-Wire Communication Setup

Standard Setup (All Systems):
For most MRCOOL Versa Pro systems, the default wiring setup utilizes a two-wire communication system between the thermostat and the air handler. This is true for systems from 18,000 to 60,000 BTU (18k to 60k).

Exceptions for 18k–30k Systems (e.g., model MVP-30-HP-C-230A00-O):

• While the standard wiring between the condenser and air handler remains 4-wire, the wiring from the air handler to the thermostat differs.
• In these systems, the wiring between the air handler and thermostat uses either the wire included in the kit or HA/HB terminal wiring.

Scenario 2: Converting to 24V for 18k–30k Systems

(Applies to early generation 30k and under models like MVP-30-HP-C-230A00-O)

Condenser to Air Handler:

• Use a 14/4 communication wire to connect terminals 1, 2, and 3 on both the condenser and the air handler.

Air Handler to Thermostat (24V):

• You will need 7 wires to run between the air handler and thermostat. If you don’t have electric heat (W1) or don’t want to stage the system (Y1 or Y2), you may need fewer wires:
  • 6 wires without electric heat (W1)
  • 5 wires if you don’t need staging (Y1 or Y2)

Terminal Designations (7-Wire Setup):

• R: 24V power
• B: Reversing valve (heat mode active)
• C: Common
• G: Indoor blower motor
• Y1: 1st stage compressor
• Y2/Y: 2nd stage compressor
• W1: Auxiliary electric heat

After Wiring:

• On the air handler’s display board, turn dip switch SW1-1 to ON.

Thermostat Setup:

• Depending on your thermostat model, access the setup menu and configure it for a staged heat pump (or non-staged if wiring without Y1/Y2).
• Set the reversing valve to energize in heat mode (B), as the default on most thermostats is for cooling mode (O).

Scenario 3: Full 24V Setup for 36k–60k Systems

(Also applies to newer 30k+ models like MVP-30-HP-MUAH-230A00-O)

Scenario 1 (Standard Setup):

• The system uses 2-wire shielded cable between the condenser and air handler, landing on the S1/S2 terminals at both the condenser and air handler. These terminals are located on the side board next to the display board at the air handler.
• Be careful when wiring the condenser, as there are two plastic terminal covers. The top cover needs to be lifted to access S1/S2 for the 2-wire connection—do not confuse these with the R and C terminals which are below S1/S2.

Scenario 3 (Full 24V Wiring Throughout):

Condenser to Air Handler:

• Use shielded 18/2 cable to connect terminals S1/S2 on the condenser to terminals S1/S2 on the air handler.

Air Handler to Thermostat (24V):

• Use a 7-wire setup with the following designations:
  • R: 24V power
  • B: Reversing valve (heat mode active)
  • C: Common
  • G: Indoor blower motor
  • Y1: 1st stage compressor
  • Y2/Y: 2nd stage compressor
  • W1: Auxiliary electric heat

After Wiring:

• Change dip switch SW1-1 and SW1-4 on the air handler to ON.
• At the condenser, turn dip switch 2 to ON.

Important Notes for 24V Setup:

• The S1/S2 terminals will no longer be used in this full 24V wiring setup. Ensure the wiring is correctly connected to the 24V terminals and not the S1/S2 connections.

Key Wiring Definitions:

• R: 24V power
• C: Common
• B: Reversing valve (energized in heat mode)
• G: Indoor blower motor
• Y1: 1st stage compressor
• Y2/Y: 2nd stage compressor
• W1: Auxiliary electric heat

Conclusion

By following the appropriate wiring scenario for your MRCOOL Versa Pro system, you can ensure that your system operates efficiently, whether you're using the default two-wire communication setup or a full 24V configuration. Be mindful of dip switch settings and wire placement to avoid errors during installation and configuration.