Haier MRVII-S AU48NFIERA Installation Instructions Manual page 66

6. High pressure overhigh protection
Are connectors of pressure
in good condition?
Is high pressure switch activated?
Is pressure value detected by
pressure gauge above 3MPa?
Are stop valves in suction
pipe and liquid pipe of
outdoor unit open?
Is piping twisted or deformed?
if outdoor fan motor work properly during cooling
cycle? and if indoor fan motor and indoor EEV
work properly during heating cycle?
Is filter or heat exchanger dirty?
Is system overfed? Is there air in system?
Is reading of discharging pipe pressure
gauge oscillatory?
switch
yes
yes
yes
yes
no
yes
no
yes
Evacuate and recharge
no
Check and reconnect
no
replace PCB
no
Replace high pressure switch
no
Open stop valve
yes
Repair or
replacement
no
Check fan motor
or indoor EEV
yes
cleaning
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