Midea MCH2U-18PHH2 Service Manual page 53

IPM module protection
Check whether the voltage range
of P-N on IPM module is normal?
DC277-356V for 18-27KBtu/h;
DC277-410V for 36K-48KBtu/h
Yes
Check whether the connecting
line between main board and
the IPM module is connected
tightly
Yes
Check whether the connecting
line of the compressor is
connected correctly or tightly
Yes
Replace the IPM module,
check whether the system can
work normally?
No
Check if the outdoor fan
runs properly or the outdoor
unit ventilation is good.
No
Replace the main board; check
whether the system can work
normally?
No
Replace the compressor, check
whether the system can work
normally?
Yes
No
Connect it tightly,
No
check ok or not?
No
Connect it well, check
No
ok or not?
No
For AC fan models, please refer
to 9.4 Trouble Criterion Of Main
Parts, check whether the
resistance of the fan motor is
normal. If not, replace the fan
Yes
motor. efer to
For DC fan models, r
the solution of fan speed has
been out of control malfunction
. Find out the cause and have it
solved.
Yes
Yes
53
Check whether the input
power supply is correct?
208-230V, 1N, 60Hz
Yes
Check whether the
power supply line is
connected correctly and
tightly
Yes
Check whether the lines
in E-part box are
connected tightly
Yes
Check whether the bridge rectifiers are
normal? Use the multimeter to measure
the resistance between each two
terminals, check whether there is the
condition that value of resistance is 0
Yes
Check whether the connecting line of
every reactor is normal? If the line is
broken, the resistance of the two ports is
∞；Check whether the PFC module
broken .
Trouble is solved
Regulate it to correct, then
No check whether the system
can work normally?
No
Connect it correctly
No and tightly, check ok
or not?
No
Connect it tightly,
No
check ok or not?
No
No
Yes
Replace the bridge rectifiers
No
Replace the connecting line or
reactor or replace the PFC module