Troubleshooting 
Electrical Control  249 
d. Protection of pressure or temp. 
 
 
 
e. Temperature sensor open or short circuit 
Open or short circuit of 
temperature sensor
Check the connections 
between temperature 
sensor and PCB. Are 
the connections good?
Correct the connections.No
Yes
Yes Replace indoor or outdoor PCB.
Replace the sensor 
Check the resistance value 
of the sensor via Appendix 1
Is it normal?
No
Protection of pressure or temp. 
Is it k1 or K2 open ? 
Is temp. protective switch K1 open 
Possible reason 
1. The wires is loose to K1 
2. Air or other gas in the refrigerant.
3. Heat exchanger is dirty 
4. Outdoor fan or fan blade is 
defective 
5. Outdoor unit is in bad ventilation 
6. Refrigerant is leakage 
Is pressure protective switch K2 open
Yes 
Yes 
Yes 
Possible reason 
1. The wires is loose to K2 
2. Air or other gas in the refrigerant.
3. Heat exchanger is dirty 
4. Outdoor motor or fan blade is 
defective 
5. Outdoor unit is in bad ventilation 
6. Refrigerant is too much