88
Wellea Monobloc
4.21.6
L0 troubleshooting
Situation 1: L0 error appears immediately after the outdoor unit is powered-on
L0
Communication wire between refrigerant
system main PCB and inverter module
(10 pins) not connected properly
1
Yes
Ensure communication wire is connected
properly
No
Inverter module is damaged
2
Yes
No
Voltage between pins F0 and GND of
communication port for connection to
inverter module on the refrigerant
system main PCB is too low
3
Yes
Replace the inverter module
4
Notes:
1.
For MHC-V5(7, 9)W/D2N8, the communication port between refrigerant system main PCB and inverter module is port CN17 on refrigerant system main
PCB and port CN32 on inverter module. For MHC-V12(14, 16)W/D2N8, the communication port between refrigerant system main PCB and inverter module
is port CN6 on refrigerant system main PCB and port CN1 on inverter module. For MHC-V12(14, 16)W/D2RN8, the communication port between
refrigerant system main PCB and inverter module is port CN201 on refrigerant system main PCB and port CN1 on inverter module.
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
Figure 4-2.3 or 4-2.5 in Part 4, 2.3 “Main PCBs for Refrigerant System,
Inverter Module and Filter Boards”.
3.
The normal voltage between F0 and GND is 5V. Refer to Figure 4-4.4.
4.
When replacing an inverter module, a layer of thermally conductive silica gel should be painted on the IPM module (on the reverse side of the inverter
module PCB).
Figure 4-4.4: F0 and GND voltage on CN201
Vnormal = 5V
