Midea M-Thermal Series Service Manual page 76

L1/L2 troubleshooting
The normal DC voltage between terminals P and N on inverter module is 310V in standby and 380V when the fan motor is
running. If the voltage is lower or higher than the normal voltage, the unit displays an L1 or L2 error.
Figure 4‐4.2: Inverter module terminals
Situation 1: L1 or L2 error appears immediately after the outdoor unit is powered‐on
Power supply is abnormal
Replace the inverter module
Notes:
1. 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.
201909 75
N
L1 / L2
No
1
Midea CAC Confidential
U V W N
Re‐start the unit once the power supply
Yes
has returned to normal
M‐Thermal Split
P