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Figure 4‐4.1: Replacing an inverter module
Situation 2: L0 or L4 error appears immediately after the compressor starts up
U V W wire between inverter module and
compressor is not connected properly
Inverter module is damaged
Compressor has malfunctioned
Replace the outdoor unit main PCB
Notes:
1.
Connect the U V W wire from the inverter module to the correct compressor terminals, as indicated by the labels on the compressor.
2.
Measure the resistance between each of U, V and W and each of P and N on the inverter module. All the resistances should be infinite. If any of them are
not infinite, the inverter module is damaged and should be replaced. Refer to
3.
When replacing an inverter module, a layer of thermally conductive silica gel should be painted on the IPM module, IGBT, diode ,brigde rectifer (on the
reverse side of the inverter module PCB). Refer to Figure 4‐4.1.
4.
The normal resistances of the inverter compressor are 0.7‐1.5Ω among U V W and infinite between each of U V W and ground. If any of the resistances
differ from these specifications, the compressor has malfunctioned.
201909 73
L0 / L4
1
No
2
No
4
No
Midea CAC Confidential
Paint a layer of thermally conductive
silica gel on the PFC module
Paint a layer of thermally conductive
silica gel on the IPM module
Yes
Ensure U V W wire is connected properly
Yes
Replace the inverter module
Yes
Replace the compressor
Figure 4‐2.2 or 4‐2.4 in Part 4, 2.1 "Outdoor Unit PCBs".
M‐Thermal Split
3
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