76
Installation and Maintenance
Service Manual
6. Overload protection of compressor H3, high discharge temperature protection of compressor E4
 
(AP1 hereinafter refers to the control board of the outdoor unit)
Main detection points:
(1) electronic expansion valve (2) expansion valve terminal (3) charging amount of refrigerant   (4) overload protector
Malfunction diagnosis process:
After the unit 
de-energized 
for 20min
N
N
N
Y
N
N
Replace 
control board 
AP1
End
Remove 
malfunction?
Check refrigerant, if there is
leakage, please refer to 
specication 
Remove 
malfunction?
Replace 
overload 
protector SAT
Replace EKV 
coil of electron 
expansion valve
The resistance value of 
rst 4 lead foot and the 
fth lead foot is similar, less 
than 100Ω
Connect wire 
well with wiring 
diagram
If the wiring terminal FA of electron
expansion is well connected? 
Under ambient temperature, test the 
resistance of  overload protector  with 
ohmic meter resistance value 1000Ω
If the overload protector SAT 
iswell connected?