check if the wired controller
can match with indoor PCB
replace wired controller
no
Is power cable or compressor wire
securely connected? Properly?
Modify power supply circuit
yes
Is AC contactor in poor contact?
Is power just turned on?
check if the dip
switch position on
PCB is right
correct the position
6) Communication failure between wired controller and indoor PCB or no display on wired controller
Confirm commumication failure according
to the fault code list or no display
yes
yes
for some models, when powered on,
initialization will display 88, if initrialization
cannot finish, check indoor dip switch position
no
Is voltage between A and
B of wired controller 12V?
yes yes
yes
Is voltage between B
and C fluctuating?
replace PCB
no
no
no
Is supply transformer or 7812
component in good condition?
yes
check if wiring
is correct
check if failure disappears after
changing transformer or PCB
no
no
check if failure disappears after
changing wired controller
yes
wired controller is
broken
7) Over current protection in 3-phase fixed frequency models
Is three-phase circuit not balanced? Is
supply voltage too low? Is supply
voltage too low at compressor start-up?
yes
no
re-wiring
yes
Is compressor current more than overcurrent protection
limit? Is current detecting circuit in good condition?
Confirm detecting circuit
is abnormal,replace
outdoor PCB
no
yes
yes
replace AC contactor
yes
if compressor is normal
no
Is resistance of compressor
winding incorrect? Is it stuck?
yes
replace compressor
yes
if pressure is normal
no
Check: 1. Is a valve in system shut off;
2. Is piping clogged;
3. Is system overfed; is there air in system;
4. (Cooling cycle) Is condenser dirty? Does outdoor fan motor run at low speed or stop?
5. (Heating cycle) Is evaporator or filter dirty? Does indoor fan motor run at low speed or stop?
6. Is ambient temperature too high? Is system overloaded?
Troubleshooting
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