Haier AS25THMHRA-C Service Manual page 193

10.3.10 The communication fault between indoor and outdoor
Indoor display
outdoor display LED1 flash 15 times
Method of Communication is detected by checking the indoor PCB and the outdoor PCB.
Malfunction
Detection
Malfunction
Decision The indoor PCB broken leads to communication fault.
Conditions
Supposed
Causes
Troubleshooting * Caution Be sure to turn off power switch before connect or disconnect connector, or else
Restart the a/c and it
becomes normally.
NO
If starting up normally, but
malfunction occurs again after a while
YES
Check whether the linking
cable between the indoor and outdoor
is well connected or whether its core
wires are well insulated or its
L/N is not reversed.
YES
Check the indoor mainboard only indoor
YES
charged.
Measure the voltage between 3 and 4 of IC6
on the indoor mainboard with a multimete .And
measure the voltage between CN23(C) and
CN21(L) with a multimeter .
E7
The outdoor PCB broken leads to communication fault.
Communication wiring disconnected.
The indoor PCB is broken.
The outdoor PCB is broken.
The Module PCB is broken.
parts damage may be occurred.
(A)
The outdoor
YES
mainboard needs
dehumidification.
The outdoor
NO
mainboard needs
dedust.
Reconnect the linking
cable or replace the
linking cable with new
one.
NO
39
Service diagnosis
Domestic air conditioner