122
Installation and Maintenance
Service Manual
(2) IPM protection, phase current overcurrent (the control board as below indicates the control board 
     of outdoor unit) H5/P5
Mainly detect:
Troubleshooting:
Turn on the unit 
after energization
Whether IPM 
protection occurs after the unit has 
operated for a while? 
Measure the voltage 
between terminal L 
and terminal N with 
AC volmeter
Whether 
the voltage between 
terminal L and terminal N of XT is 
within 210AVC~
250VAC?
1. Whether the heat exchangers of indoor unit and outdoor unit are 
dirty? Whether the radiation is affected because the unit is 
covered by the objects? 
2. When indoor fan and outdoor unit are operate normally?
3. Whether the system pressure is too high?
4. Whether the pressure is because there's too much refrigerant? 
Check the power 
supply voltage and 
make the power voltage 
resume to the range 
of 210VAC~250VAC
Correctly connect the wires of 
compressor according to the 
electric wiring diagram, and 
then turn on the unit
Check the connection 
between the control board 
and the compressor by 
referring to the electric 
wiring diagram
Check whether wires 
of compressor (UVW) are connected 
correctly
Measure the resistance value 
among three terminals (UVW) 
of compressor with a resistance 
measuring meter. 
Whether the 
resistance value of three terminals 
are almost the same. 
Measure the resistance 
between three terminals (UVW) 
of compressor and the copper pipe 
with resistance measuring meter
Whether the 
resistance value is more than 
500ohm?
Replace the 
compressor 
Whether there's 
abnormal phenomenons 
described as above? 
Whether the unit 
can operate normally? 
Replace control 
board
End
Correct it one by one 
according to the Service 
Manual, and then turn on 
the unit. 
(1) Compressor COMP terminal  (2) voltage of  power supply (3) compressor 
(4) Refrigerant-charging volume  (5) air outlet and air inlet of outdoor/indoor unit