Error 425 — Phase reversal or phase failure (3-phase unit)

What does 425 mean?

For 3-phase outdoor units, this error indicates that the incoming power phases (R-S-T-N) are reversed or one phase is missing. This can damage the compressor.

• Incorrect wiring of the 3-phase power supply
• Power supply issue (missing phase)
• Faulty phase detection circuit

Click steps to track your progress.

1. 1

   Immediately turn off power to the unit.

2. 2

   Verify the wiring of the R, S, T, and N connections for the 3-phase power supply.

3. 3

   Check the incoming power source for phase issues.

4. 4

   An electrician or qualified technician must correct the wiring or power supply problem.