Midea M3OF-27HFN1-M - Over-Voltage or Under-Voltage Protection Diagnosis and Solution

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7.4.1.7 Over-voltage or under-voltage protection diagnosis and solution.
Voltage protection
Check the voltage of
outdoor unit power supply,
whether the voltage
between L(L1) and N (L2) is
about 187~253VAC
Check the power supply
Check whether the voltage
of IPM board P and N is
normal? DC277-356V for
18-27KBtu/h; DC277-410V
for 36KBtu/h
Replace bridge rectifiers,
and then check whether the
system can run
normally(Only for qua-
zone)
Replace IPM board, and
then check whether the
system can run normally
Replace outdoor main board
Yes
No
No
No
No
Yes
Trouble is solved
Yes
Yes