>a__WcU[S^ <[c >a`V[e[a`Wc
yes
if outdoor stop valves of gas pipe 
and liquid pipe are open totally
Open the valves
no
Is indoor filter or heat 
exchanger dirty?
Cleaning
yes
yes
Repair fan motor or fan 
capacitor
no
no
Repair pipe
yes
Is piping twisted or deformed?
yes
Does indoor fan work properly during 
cooling cycle? Does outdoor fan work 
properly during heating cycle?
no
Check if system is overfed according 
to equalized pressure in halt.
yes
Evacuate and recharge
no
Is reading of discharging pressure 
gage oscillatory?
no
Bad operation codition, such as ultra low 
outdoor temperature
yes
There is air in system. 
Evacuate and recharge
4) High pressure protection
Confirm the fault according 
to the fault code list
yes
Check and reconnect
no
Are connectors of pressure switch in good 
condition?
Is high side pressure switch 
activated? (If not, DC voltage is 0V.)
yes
Replace PCB
no
Is the high side pressure detected by 
the gage higher than threshold 
value? The threshold value is 
indicated on the switch
yes
Replace high pressure 
switch
no
 
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