Century B-VMH36SD-1 Service Manual page 41

Service Manual - VMH 9/12/18/24 SU & VMH30/36S D Series
For 24K~36K:
At first test the resistance between all points; U, V, W of IPM and P, N. If any result is 0 or close to 0, the
IPM is defective. If OK, please follow the procedure below:
Check whether the power
voltage is normal
Measure whether outdoor
terminal voltage is normal?
Measure whether the voltage
between L and N is normal?
Measure whether input voltage of
bridge rectifier is normal?
Measure whether the voltage
between P and N is normal
(refer to Appendix 4)?
Measure whether the
connecting wire between main
board and the IPM board is
connected tightly
Check whether the connecting
wire of the compressor is
connected correctly or tightly
Check if the outdoor unit
ventilation is good
Check if the outdoor fan
runs properly
Replace IPM board
Replace the outdoor main PCB
Check that the
compressor is normal
Check whether the refrigerant system is OK.
Restart the unit when the power
supply is normal
Power connections
Check the wiring
of L and N
Check the wiring
of bridge rectifier
Reconnect
Reconnect
Provide ventilation
Please refer to the solution of [fan
speed has been out of control
malfunction] to correct problem.
Replace the compressor
39
Reconnect
Reconnect
Reconnect
Check whether bridge
rectifier is normal
Replace the PFC module (if applicable)
Check the wiring of
reactor or inductor
Check whether
reactor or inductor
is normal
Replace the bridge rectifier
Reconnect the wiring
Replace reactor
or inductor