4220 — Voltage shortage, Overvoltage, or Power synchronization error

What does 4220 mean?

This code indicates issues with the power supply, such as the voltage being too low (shortage voltage trouble), too high (overvoltage trouble), or a problem with power synchronization. It can also point to a PAM (Pulse Amplitude Modulation) error or an L1 open-phase in the electrical connection. Specific sub-codes (3, 6, 7, 8) can be viewed via SW1 on the outdoor controller board for more detail.

• Unstable power supply voltage (too high or too low).
• An open-phase in the power supply (T open-phase).
• Disconnected compressor wiring or other vital control board connectors (CN52C, CN5, CN2).
• Malfunction of the outdoor power board or outdoor controller board.
• Issues within the PAM circuit.

Click steps to track your progress.

1. 1

   Check your building's power supply facility for any known voltage fluctuations, recent outages, or breaker trips.

2. 2

   Inspect all external wiring connected to the outdoor unit for any visible signs of disconnection, damage, or improper connection.

3. 3

   If specific sub-codes (3, 6, 7, 8) are displayed by operating SW1 on the outdoor controller board, note them down as they provide more precise fault information.

4. 4

   Turn off the main power to the unit at the circuit breaker, wait at least 30 seconds, then turn it back on to attempt a system reset.