MRCOOL Versa Pro System Wiring Guide: 1.5-5 Ton Models

When it comes to wiring the MRCOOL Versa Pro HVAC systems, understanding the specific wiring needs for different tonnages is crucial for a successful installation. This guide provides a breakdown for 1.5-2.5 ton models (MVP-18, 24, 30) and 3-5 ton models (MVP-36, 48, 60), ensuring that your setup runs smoothly.

1.5-2.5 Ton Wiring (MVP-18, 24, 30 Models)

For these models, the wiring setup between the condenser and the air handler is similar to that of a mini-split system. A 14/4 communication wire is used, connecting terminals 1, 2, and 3 on both the condenser and the air handler.

• Power Supply: In this configuration, the condenser provides power to the air handler, so a separate power connection from the main breaker to the air handler is only necessary if you’re installing a heat kit.

3-5 Ton Wiring (MVP-36, 48, 60 Models)

For larger models, the wiring setup is slightly different. Both the condenser and air handler must be powered independently from the main breaker.

• Communication Wire: A shielded 18/2 cable connects terminals S1/S2 on the condenser to terminals S1/S2 on the air handler.

Thermostat Connections (All Models)

All models use a communication wire to connect the air handler to the thermostat. Often, a grey communication wire with pigtails is provided for this connection.

• Thermostat Wiring:
  • Red Pigtail Connection: The pigtail with the red end should be connected to the Molex connector located on the air handler’s display board, which is labeled "S 485" at the bottom right.
  • Blue Pigtail Connection: The pigtail with the blue end should be connected to the Molex connector on the thermostat.
  • Grey Wire Connection: Once both pigtails are connected, use the long grey wire to link them, allowing for seamless communication between the thermostat and the air handler.

  By following these steps, you'll ensure a smooth setup and effective communication between your system components.
• Alternative Wiring: If the grey wire is unavailable or too short, an 18/2 shielded cable can be used, connecting terminals HA/HB on the air handler’s display board to terminals HA/HB on the thermostat.
• Power Source: The thermostat is powered directly by the air handler, with the thermostat battery only serving as a memory backup.

Important Notes:

• When installing or replacing components, always ensure the wiring is done correctly to prevent system malfunctions.
• Double-check power sources to avoid confusion, especially when installing additional components like heat kits.

By following these wiring instructions, your MRCOOL Versa Pro system should operate efficiently and effectively.