DIAGNOSTIC CODES 
No.
1
2
3
4
5
6
Description
If outdoor unit detects the high pressure switch is cut off for 3-sec
successively, high pressure protection will occur. All the loads 
(except the 4-way valve in heating mode) will be switched off. 
In this case, all the buttons and remote control signals except
ON/OFF button will be disabled and system won't be recovered 
automatically. Switch off the unit or re-energize the unit after 
cutting off power to eliminate this protection.
If indoor unit detects the evaporator temperature is lower than 
protective temperate value after the unit has been running for a 
period of time under cooling or dry mode, the unit will report this fault,
in which case the compressor and outdoor fan motor will be stopped.
The unit will not run until evaporator temperature is higher than 
the protective temp. value and the compressor is stopped for 3-min.
If outdoor unit detects low-pressure switch is open during ON or
standby state within 30-sec successively the unit will report a low
pressure protection. If the fault occurs 3 times successively within
30-min, the unit will not recover automatically.
If the unit reports low refrigerant level within 10-min after turning on
the unit, the unit will stop operation. If the fault occurs successively 
3 times, the unit cannot be recovered automatically.
If the unit enters refrigerant recovery mode through special 
operation, E3 will be displayed. After exiting refrigerant recovery
mode, the code will disappear.
If outdoor unit detects the discharge temperature is higher than 
protective temperature value, the unit will report high discharge
temperature protection. If the protection occurs over 6 times, the
unit cannot be recovered automatically. Switch off the unit or 
re-energize the unit after cutting off power to reset this protection.
If the outdoor unit does not receive data from indoor unit, 
communication malfunction will be reported. If there is 
communication abnormality between display board and indoor 
unit, communication malfunction will be reported.
If the indoor unit does not receive signal from indoor fan motor 
for 30-sec successively when the fan motor is operating, indoor 
fan motor malfunction will be reported. In this case, the unit can 
automatically resume operation after stopping. If the malfunction
occurs 6 times within one hour, the unit cannot be recovered 
automatically. Switch off the unit or re-energize the unit after 
cutting off power to eliminate this malfunction.
Error 
Code
E1
E2
E3
E4
E6
E8
Malfunction
Name
High Pressure
Protection
Indoor Coil
Freeze 
Protection
Low Pressure 
Protection
Low 
Refrigerant
Protection
Refrigerant
Recycling
Mode
Compressor
High Discharge
Temperature
Protection
Communication
Malfunction
Origin of 
Malfunction
High Pressure
Switch
Indoor
Evaporator
Temperature
Sensor
Low Pressure 
Switch
Compressor
Discharge
Temperature
Communication
Failure Between
Indoor and 
Outdoor Main
Board
Indoor 
Fan Motor
Error Codes
The U-Match System has on board diagnostics. The indoor unit and Tether Controller will display 
error codes. The following is a summary of the codes with explanation: 
31