GREE              Duct type Ducted Type Split Air-Conditioner Units 
89 
Troubleshooting: 
Yes
No
No
“b2”Defrosting 
temperature sensor 1 
error
Is the terminal between 
mainboard and ambient temperature 
sensor loose or any foreign objects 
inside the terminal?
If it is loosened or there 
are foreign objects, 
retighten it after 
treatment.
Check if the temperature 
sensor is abnormal
Yes
Replace the 
temperature sensor
Check if the circuit is 
abnormal
Yes
Replace the main 
control board
 
(15)   “b9” malfunction of gas exit temperature sensor for heat exchanger 
Fault display: the main board of outdoor unit and indoor unit will display  . 
Applicable model: all outdoor units. 
Judgment condition and method for the fault
: 
Sample the AD value of temperature sensor through temperature sensor detecting circuit and judge 
the range of AD value, if the sampling AD value exceeds upper limit and lower limit in 30 seconds 
continuously, report the error. 
Possible reason
: 
1)  Poor contact between ambient temperature sensor and terminal in mainboard interface. 
2)  Temperature sensor is abnormal. 
3)  The detected circuit is abnormal.