Whether the wiring 
between the high pressure 
switch and main control 
board is connected well or 
correctly
 Whether the wiring 
between the high pressure 
switch and main control 
board is connected well or 
correctly
Method: Disconnect the plug. 
Measure the resistance of the 
high pressure protector, if 
the protector is normal the 
value is o,
Method: Disconnect the plug. 
Measure the resistance of the 
high pressure protector, if 
the protector is normal the 
value is o,
Yes
Yes
Connect it well
Connect it wellNo
Replace high pressure protector
Replace high pressure protectorNo
 Whether the high 
pressure protector 
is broken
 Whether the high 
pressure protector 
is broken
 Check whether the outdoor 
ambient temperature is 
higher than 50℃
 Check whether the outdoor 
ambient temperature is 
higher than 50℃
No
Stop the unit 
Stop the unit Yes
Check if the outdoor unit 
ventilation is good
Check if the outdoor unit 
ventilation is good
Yes
Make the outdoor unit ventilate well
Make the outdoor unit ventilate well
 Check whether the heat 
exchanger is dirty
 Check whether the heat 
exchanger is dirty
No
Clean the heat exchanger
Clean the heat exchangerYes
Check whether the refrigerant 
system is ok
Check whether the refrigerant 
system is ok
 Replace outdoor main 
board
 Replace outdoor main 
board
No
High pressure protection 
High pressure protection 
Check if the outdoor fan runs 
properly
Check if the outdoor fan runs 
properly
please refer to the solution of fan 
speed has been out of control 
malfunction . Find out the cause and 
have it solved.
please refer to the solution of fan 
speed has been out of control 
malfunction . Find out the cause and 
have it solved.
No
Yes
NO