Midea M2OC-18HFN1-M Service Manual page 65

9.4.2.5 E5(Voltage protection) error diagnosis and solution.
Error Code
Malfunction decision
conditions
Supposed causes
Trouble shooting:
between L(L1) and N (L2) is
and then check whether the
Replace outdoor main board
E5
An abnormal voltage rise or drop is detected by checking the
specified voltage detection circuit.
● Power supply problems.
● System leakage or block
● PCB faulty
Voltage protection
Check the voltage of
outdoor unit power supply,
whether the voltage
about 187~253VAC
Yes
Check whether the voltage
of IPM board P and N is
normal? DC277-356V for
18-27KBtu/h; DC277-410V
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