Haier N-Series Service Manual page 41

10.3.6 The communication fault between IPM and outdoor PCB
Outdoor display: LED1 flash 4 times
Method of Communication is detected by checking the IPM module and the outdoor PCB
Malfunction
Detection
■ The outdoor PCB broken leads to communication fault
Malfunction
■ The IPM module broken leads to communication fault
Decision
Conditions
■ The outdoor PCB is broken
Supposed
■ The IPM module is broken
Causes
■ Communication wiring disconnected
Troubleshooting * Caution Be sure to turn off power switch before connect or disconnect connector,
else parts damage may be occurred.
1) Check whether plug of MODULE COM and MODULE POWER on the outdoor
PCB and IPM module is tight connected
2) Check whether the connection of P & N wire between IPM and outdoor is tight
Is the connection OK?
1.Check whether the voltage between 1
and 2 of Module Power
is about DC5V,
2.Check whether the voltage between2
and 3 of Module Power is about DC15V,
Replace outdoor PCB
NO
Malfunction unsolved
YES
NO
39
1) Pull out and reinsert the terminals.
2) Replace connected wire
YES
Replace power module
Domestic air conditioner
Seivice diagnosis
or