Midea MS11M-09HRFN1-BW0W Service Manual page 49

For 24K~36K:
At first test the resistance between every two ports of U, V, W of IPM and P, N. If any result of
them is 0 or close to 0, the IPM is defective. Otherwise, please follow the procedure below:
Check whether the power voltage
Check whether the power voltage
is normal.
is normal.
Yes
Measure whether outdoor terminal
Measure whether outdoor terminal
voltage is normal？
voltage is normal？
Yes
Measure whether the voltage
Measure whether the voltage
between L and N is normal？
between L and N is normal？
Yes
Measure whether input voltage of
Measure whether input voltage of
bridge rectifier is normal？
bridge rectifier is normal？
Yes
Measure whether the voltage
Measure whether the voltage
between P and N is normal
between P and N is normal
refer to the Appendix 4？
refer to the Appendix 4？
Yes
Check whether the connecting
Check whether the connecting
wire between main board and the
wire between main board and the
IPM board is connected tightly
IPM board is connected tightly
Yes
Check whether the connecting
Check whether the connecting
wire of the compressor is
wire of the compressor is
connected correctly or tightly
connected correctly or tightly
Yes
Check if the outdoor unit
Check if the outdoor unit
ventilation is good
ventilation is good
Yes
Check if the outdoor fan runs
Check if the outdoor fan runs
properly
properly
Yes
Replace IPM board
Replace IPM board
No
Replace the outdoor main PCB
Replace the outdoor main PCB
No
Check the compress is
Check the compress is
normal
normal
Yes
Check whether the refrigerant system is ok
Check whether the refrigerant system is ok
Restart the unit when the power supply
Restart the unit when the power supply
No
Check the wiring of
Check the wiring of
No power wires well or
power wires well or
correctly
correctly
Check the wiring of L
Check the wiring of L
No
and N well or correctly
and N well or correctly
Check the wiring of
Check the wiring of
No bridge rectifier well or
bridge rectifier well or
correctly
correctly
No
No Reconnect it well
Reconnect it well
No Reconnect it well
Reconnect it well
No Make the outdoor unit ventilate well
Make the outdoor unit ventilate well
please refer to the solution of [fan speed
please refer to the solution of [fan speed
No
has been out of control malfunction] .
has been out of control malfunction] .
Find out the cause and have it solved.
Find out the cause and have it solved.
No Replace the compressor
Replace the compressor
47
gets normal
gets normal
Reconnect it well
Reconnect it well
Reconnect it well
Reconnect it well
Reconnect it well
Reconnect it well
Check whether bridge
Check whether bridge
rectifier is normal
rectifier is normal
Yes
Replace the PFC module(If has)
Replace the PFC module(If has)
No
Check the wiring of reactor
Check the wiring of reactor
or inductance
or inductance
Yes
Check whether reactor or
Check whether reactor or
inductance is normal
inductance is normal
Yes
No Replace the bridge rectifier
Replace the bridge rectifier
No Reconnect the wiring
Reconnect the wiring
Replace reactor or
Replace reactor or
No
inductance
inductance