VRF Troubleshooting

VRF Error Codes Explained.

Look up your error code below. We'll tell you what it means, how serious it is, and what to do next. If you need a tech, we dispatch same day for VRF systems across NYC.

22 error codes

E1Service Needed

Remote controller communication error

Check wiring between remote controller and indoor unit. Reset power. If persists, call a tech.

E2Service Needed

Indoor/outdoor unit communication error

Check communication wiring. Verify address settings. Reset system power for 30 seconds.

E3Minor

Remote controller signal receive error

Check for interference. Replace remote batteries. Re-pair if wireless.

E6Call a Tech

Indoor unit communication error (inter-unit)

Communication fault between indoor units. Check transmission line. Requires technician.

E7Call a Tech

Outdoor unit communication error (inter-unit)

Communication between outdoor units failed. Check wiring and PCB. Call for service.

E8Service Needed

Communication error (between indoor and M-NET)

M-NET controller issue. Verify address and wiring. May need board replacement.

E9Service Needed

Communication error (between M-NET controllers)

Cascaded controller communication failure. Check all M-NET wiring and terminators.

U1Call a Tech

High pressure protection activated

System shut down on high head pressure. Check for dirty condenser coil, blocked airflow, or refrigerant overcharge. Call for service.

U2Call a Tech

Low pressure protection / refrigerant shortage

Possible refrigerant leak. System needs professional leak detection and repair. Do not reset repeatedly.

U3Call a Tech

Compressor overcurrent trip

Compressor drawing too much current. Could be failing compressor, wiring issue, or locked rotor. Requires technician.

U4Call a Tech

Thermistor fault (discharge pipe)

Discharge pipe temperature sensor open or short. Sensor replacement needed.

U5Service Needed

Thermistor fault (condenser)

Condenser temperature sensor failure. Check connections. May need sensor replacement.

U6Call a Tech

Compressor overcurrent (during start)

Compressor cannot start. Check power supply voltage, wiring, and compressor condition.

U8Call a Tech

Outdoor unit fan motor fault

Fan motor stopped or running erratically. Check motor, capacitor, and control board.

U9Call a Tech

Abnormal voltage detection

Power supply voltage out of range. Check building power. May need electrician + HVAC tech.

UACall a Tech

High pressure protection (heat mode)

Indoor coil too hot in heating mode. Check for restricted airflow or dirty filters.

FbService Needed

Indoor unit fan motor error

Fan motor stopped. Check motor connections. Clean fan wheel. May need motor replacement.

P1Service Needed

Intake sensor error

Room temperature sensor fault. Check connector. Replace sensor if damaged.

P2Service Needed

Pipe temperature sensor (indoor heat exchanger)

Coil temperature sensor fault. Sensor may need replacement.

P4Service Needed

Drain sensor error / float switch activated

Condensate drain blocked or float switch tripped. Clear the drain line.

P5Service Needed

Drain pump error

Condensate pump failed. Check pump operation and wiring. May need pump replacement.

P8Service Needed

Pipe temperature error (2nd heat exchanger)

Sub-cool sensor fault. Check sensor and connections.

Got a VRF error code?

Don't reset it 10 times hoping it goes away. Call us. We're certified Mitsubishi, Daikin, and Fujitsu techs. We'll diagnose it right the first time.