Service Manual

8.4.1.3 zero-crossing signal error diagnosis and solution.
Malfunction decision
conditions
When PCB does not receive zero crossing signal feedback for
4 minutes or the zero crossing signal time interval is abnormal.
Supposed causes
● Connection mistake
● PCB faulty
Trouble shooting:
Check if the connections and
power supply is normal?
Correct the connections. Turn on the
unit when the power supply is good.
No
Yes
Indoor main PCB is
defective. Replace indoor
main PCB.