Midea MCH2U-18PHH2 Service Manual page 67

8.4.2.5 E5 (Over-voltage or under-voltage protection) diagnosis and solution.
Error Code
Malfunction conditions
Potential causes
Trouble shooting:
Voltage protection
Check the voltage of
outdoor unit power supply,
whether the voltage
between L(L1) and N (L2) is
about 187~264VAC
Yes
Check whether the voltage of IPM
board P and N(GND) is normal?
DC277—356V for 2-zone(18K Btu/h)/3
zone(27K Btu/h)
DC277-410V For 4-zone(36K Btu/h)/5-
zone(48K Btu/h)
No
Replace bridge rectifiers,
and then check whether the
system can run normally
5-zone)
No
Replace IPM board, and
then check whether the
system can run normally
No
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
● Faulty PCB
No Check the power supply
(for
Yes
Yes
Yes
Trouble is solved
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