Service Manual
(9) Malfunction of Overcurrent Protection E5
Main detection points:
● 
Is the supply voltage unstable with big uctuation?
● 
Is the supply voltage too low with overload?
● 
Hardware trouble?
Malfunction diagnosis process:
5. Malfunction of Overcurrent Protection
Main detection points:
● Is the supply voltage too low with overload?
● Hardware trouble?
Malfunction diagnosis process: 
 
 
 
   
 
no 
no 
no 
no 
yes 
no 
no 
 
 
End 
yes 
Malfunction is 
eliminated
Is the supply voltage unstable
 with big fluctuation?
Start
Is the supply voltage too low 
with overload?
       The fan is abnormal? Fan 
speed is too low or fan doesn’t rotate
                           Measure the 
              current of live wire on the main 
     board with a clamp ampere meter. Is the 
       current higher than the value of the 
                 overcurrent protection?
                           Is there blockage inside 
               the system? (Filth blockage, ice plug, 
   greasy blockage, the cut off valve hasn’t been 
 
                                 opened completely)
                           Is the compressor running
          abnormally? Is there abnormal sound or oil 
              leakage; is the temperature of the shell 
                                  too high, etc.?
                Is the indoor / outdoor 
heat exchanger dirty,or are the air inlet  
                and outlet blocked?
Normal fluctuation should be within 10 % of the 
rated voltage on the nameplate
Malfunction is 
eliminated
no 
yes 
no 
yes 
no 
 
yes 
no 
no 
no 
yes 
no 
yes 
no 
yes 
yes 
yes 
yes 
yes 
yes 
yes 
Malfunction is 
eliminated
Malfunction is 
eliminated
Malfunction is 
eliminated
Malfunction is 
eliminated
Malfunction is 
eliminated
Malfunction is 
eliminated
Adjust the supply voltage to maintain it within 
normal range
Clean the indoor and outdoor heat exchangers 
and remove the blockage of air inlet and outlet
Check the motor and reinstall the motor to have
the fan run normally
Replace the mainboard with the same model
Replace the compressor
Flush the heat exchangers with high pressure 
nitrogen
Replace the mainboard with 
the same model