Haier H-MRV Series Service Manual page 184

7. High pressure overhigh protection: 12 flashes of outdoor LED302 When is high pressure switch
activated: Pressure is above 3.0 MPa.
Are connectors of CN318 pressure
switch in good condition?
Is high pressure switch activated?
Is pressure value detected by
pressure gage 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?
yes
yes
yes
yes
no
yes
no
yes
Evacuate and recharge
>a__WcU[S^ <[c >a`V[e[a`Wc
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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