20
DIAGNOSTIC CODES
X-fan Mode
Indoor Evap Coil Temperature
Sensor Malfunction
Gas valve temperature sensor
is open/short circuited
System Configuration
Malfunction
Communication wire error or
electronic expansion valve
malfunction
Wrong connection of communication
wire or malfunction of electronic
expansion valve
System High Pressure
Indoor Anti-Freeze Protection
Low Pressure Protection
Compressor High Discharge
Temperature Protection
Overcurrent Protection
Communication Malfunction
Mode conflict (Indoor units
calling for simultaneously
Heating and Cooling)
Operation status
1) Loose or bad connection between sensor and control board
2) Indoor Evap Coil temperature sensor damaged
3) Control board malfunction
Hardware malfunction
1) No jumper cap inserted on the control board
2) Incorrect or damaged jumper cap on control board
3) Indoor and outdoor units are not compatible
Operation status
Hardware malfunction
1) Over charged with refrigerant
2) Blocked or dirty outdoor coil
3) Extreme outdoor ambient conditions
1) Low return airflow
2) Indoor fan speed is too low
3) Indoor coil is blocked or dirty
1) Low on refrigerant
2) Pressure sensor is damaged
Please refer to the malfunction analysis (discharge
temperature, overload) in service manual
1) Supply voltage is unstable
2) Supply voltage is too low and system load is too high
3) Indoor coil is blocked or dirty
1) Communication cable is mis-wired between indoor
and outdoor units
2) Indoor or Outdoor control board malfunction
Operation status
AL
b5
b7
C5
dd
dn
E1
E2
E3
E4
E5
E6
E7
Yellow
3 flashes
and 1 sec Off
7 flashes
and 1 sec Off
5 flashes
and 1 sec Off
Continuous
On
Red
9 flashes
and 1 sec Off
Troubleshooting
The unit has onboard diagnostics. The outdoor unit will provide status indicators. The indoor
wall unit and remote controller will display error codes. The following is a summary of the
codes with explanation:
Indoor Unit
& Remote
Display
Outdoor Unit Indicators
Malfunction Name
Possible Causes