Faulty Inverter PCB Daikin VRV-3

[martinoff]

Joe
Have you considered that invertors DO NOT like unstable electrical supplies and voltage fluctuations.

Given a 25% plus failure rate my guess is it's not the PCB's that are at fauly!
Grizzly

THIS +100
also check the voltage difference in the three phase current. There must NOT be much difference (lets say 10~15 V will be safe)