Service Manual
40
Installation and Maintenance
9. Maintenance
9.1 Error Code List
No.
Malfunction 
Name
Display 
Method 
of Indoor 
Unit
A/C Status Possible Causes Maintenance measures
Nixie 
tube 
display
1
Indoor ambient 
temperature 
sensor is open/ 
short-circuited
F1
The unit will stop 
operation as it reaches 
the temperature point. 
During cooling and drying 
operation, except IDU fan 
motor operates, other loads 
stop operation; During 
heating operation, the 
heating fan motor operates 
according to the conditions 
of blowing residual heat.
1. The wiring terminal between indoor 
ambient temperature sensor and 
maiboard is loosened or poorly contacted;
Refer to Malfunction 
Detection Flowchart
2. There’s short circuit due to trip-over of 
the parts on maiboard;
3. Indoor ambient temperature sensor is 
damaged (Please check it by referring 
to the resistance table for temperature 
sensor);
4. Mainboard is broken.
2
Indoor 
evaporator 
temperature 
sensor is open/
short-circuited
F2
The unit will stop 
operation as it reaches 
the temperature point. 
During cooling and drying 
operation, except IDU fan 
motor operates, other loads 
stop operation; During 
heating operation, the 
heating fan motor operates 
according to the conditions 
of blowing residual heat.
1. The wiring terminal between indoor 
evaporator temperature sensor and 
maiboard is loosened or poorly contacted;
Refer to Malfunction 
Detection Flowchart
2. There’s short circuit due to trip-over of 
the parts on maiboard;
3. Indoor evaporator temperature sensor 
is damaged (Please check it by referring 
to the resistance table for temperature 
sensor);
4. Mainboard is broken.
3
Outdoor ambient 
temperature 
sensor is open/ 
short-circuited
F3
The unit will stop 
operation as it reaches 
the temperature point. 
During cooling and drying 
operation, the compressor 
stops operation while IDU 
fan motor operates; During 
heating operation, the 
heating fan motor operates 
according to the conditions 
of blowing residual heat.
1. The wiring terminal between outdoor 
ambient temperature sensor and 
maiboard is loosened or poorly contacted;
Refer to Malfunction 
Detection Flowchart
2. There’s short circuit due to trip-over of 
the parts on maiboard;
3. Outdoor ambient temperature sensor 
is damaged (Please check it by referring 
to the resistance table for temperature 
sensor);
4. Mainboard is broken.