Haier HSU24VHG(DB)-G&W - The Communication Fault between Ipm and Outdoor Pcb

Service Diagnosis
55
Domestic Air Conditioner
7.3.5 The communication fault between IPM and outdoor PCB
Outdoor display LED1 flash 4 times Indoor Display F3
Method of Communication is detected by checking the IPM module and the outdoor PCB.
Malfunction
Detection
Malfunction  The outdoor PCB broken leads to communication fault
Decision  The IPM module broken leads to communication fault
Conditions
Supposed  The outdoor PCB is broken
Causes  The IPM module is broken
Ƶ
Communication wiring disconnected
Troubleshooting * Caution Be sure to turn off power switch before connect or disconnect connector, or
else parts damage may be occurred.
YES
1) Check whether Terminal CN23 and CN24 on the outdoor mainboard
CN10 and CN11 on IPM module
2) Check whether the connected wire between IPM and outdoor
Are they good?
NO
YES
Electrify the machine again and turn it
on, Check whether the voltage between
1 and 2 of Terminal CN23 is about
DC5V, Check whether the voltage
between2 and 3 of Terminal CN23 is
about DC15V,
Replace the outdoor mainboard with a new one
Replace the outdoor IPM module
with a new one.
NO
Malfunction unsolved
1) Pull out and reinsert the terminals.
2) Replace connected wire