Midea M4OC-36HRFN1-M - Over;Under Voltage Protection Diagnosis

9.4.1.7 Over voltage or too low 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