What Are Error Codes? 

Troubleshooting A P1 or P4 Error Code:

A P1 or P4 error code might mean an abnormal rise or drop in the voltage of your MRCOOL system. Or, it can mean you need to release the refrigerant in your MRCOOL unit.

When you see a P1 or P4 error code on your MRCOOL mini split, first turn the unit off. Then turn it back on after waiting two minutes. If the problem persists, go to the outdoor unit. Remove the side wiring cover with a screwdriver. Then, using a multi-meter, test the voltage. For a unit running off of 120 volts, place the ends on L1 and ground. For a unit running off of 240 volts, touch the ends to L1 and L2.

Also, you should check to make sure the refrigerant valves are open all the way. You can achieve this with the right size allen wrench. It is important you don't force it. Just make sure the valves are open.

If these steps don't correct the P1 or P4 error code, it's important that you call the MRCOOL Warranty department at (270) 366-0457  so they can help you figure out what may be causing the P1 or P4 error code.

• List of MRCOOL Error Codes and their meaning: 

• E0 - Indoor unit EEPROM parameter error

• E1 - Indoor / outdoor units communication error

• E2 - Zero-crossing signal detection error

• E3 - Indoor fan speed has been out of control

• E4 - Indoor room temperature sensor T1 open circuit or short circuit

• E5 - Evaporator coil temperature sensor T2 open circuit or short circuit EC - Refrigerant leakage detection

• F0 - Overload current protection

• F1 - Outdoor ambient temperature sensor T4 open circuit or short circuit

• F2 - Condenser coil temperature sensor T3 open circuit or short circuit

• F3 - Compressor discharge temperature sensor TP open circuit or short circuit

• F4 - Outdoor unit EEPROM parameter error

• F5 - Outdoor fan speed has been out of control

• P0 - IPM malfunction or IGBT over-strong current protection

• P1 - Over voltage or over low voltage protection

• P2 - High temperature protection of IPM module or compressor top

• P3 - Outdoor ambient temperature too low

• P4 - Inverter compressor drive error

• P5 - Indoor units mode conflict (multi-zone ONLY)

• P6 - Low pressure protection(Only for 36K)

**If you need further assistance in troubleshooting your MRCOOL error code, it's important that you call the MRCOOL Warranty department at (270) 366-0457  so they can help you figure out how to resolve your error code issue**