Midea M2OC-18HFN1-M Service Manual page 53

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