Service Manual
33
Installation and Maintenance
9.Troubleshooting
9.1 Judgement by Flashing LED of Indoor
No.
Malfunction
Name
Error
Code
A/C Status
Possible Causes
1
High pressure
protection
E1
During cooling and drying
operation, except indoor
fan operates, all loads
stop operation. During
heating operation, if it is
inverter unit, the complete
unit stops; if it is floor
standing unit, the complete
unit stops and operation
of remote controller or
controller is unavailable.
1. The main board and the display panel are not connected well.
2. The OVC terminal on main board is not connected well with the
high pressure switch on the complete unit.
3. The wiring of high pressure switch is loosened.
4. Refrigerant is superabundant.
5. Poor heat exchange (including blocked heat exchanger and bad
radiating environment ).
6. Ambient temperature is too high.(if it is 3-phase unit, the high
pressure protection may be caused by overcurrent protection due to
this reason)
7. The supply voltage is abnormal.(if it is 3-phase unit, the high
pressure protection may be caused by overcurrent protection due to
this reason)
8. The air intake and air discharge at indoor / outdoor heat
exchanger are not smooth. The air cycle is short circuited.
9. Filter and heat exchange fins of indoor/outdoor units are blocked.
10. The system pipeline is blocked.
11. The gas valve and liquid valve for outdoor unit are not
completely opened.
12. The OVC input is at high level.
2
Freeze
protection
E2
During cooling and drying
operation,compressor and
outdoor fan stop while
indoor fan operates.
1. Poor air-return in indoor unit.
2. Abnormal fan speed.
3. Dirty evaporator.
4. System is normal, but the indoor tube temperature sensor is
abnormal, or the tube temperature sensor is not connected well.
3
Low pressure
protection of
compressor
E3
The complete unit
stops
1. The main board and display panel are not connected well.
2. The LPP terminal on the main board is not connected well with
the high pressure switch on the complete unit.
3. The wiring of the high pressure switch is loosened. High pressure
switch is damaged or poorly contacted.
4. Insufficient or leaking out refrigerant.
5. The LPP input is at high level.
4
High discharge
temperature
protection
of compressor
E4
During cooling and drying
operation, compressor
and outdoor fan stop while
indoor fan operates. During
heating operation,all loads
stop.
1. Abnormal system (e.g.: blockage, etc)
2. Abnormal rotation speed of outdoor motor (cooling )
3. Abnormal air intake (cooling)
4. System is normal, but the compressor discharge temperature
sensor is abnormal or poorly contacted.
5
Overcurrent
protection
E5
During cooling and drying
operation, compressor and
outdoor fan stop while
indoor fan operates. During
heating operation, all loads
stop.
1. Unstable supply voltage. Normal fluctuation shall be within 10%
of the rated voltage on the nameplate.
2. Supply voltage is too low and load is too high.
3. Measure the current of live wire on main board. If the current
isn’t higher than the overcurrent protection value, please check the
controller.
4. The indoor and outdoor heat exchangers are too dirty, or the air
inlet and air outlet are blocked.
5. The fan motor is not running. Abnormal fan speed: fan speed is
too low or the fan doesn’t run.
6. The compressor is not running normally. There is abnormal
sound, oil leakage or the temperature of the shell is too high, etc.
7. There’s blockage in the system. (filth blockage, ice plug, greasy
blockage, Y-valve hasn’t beenopened completely)
Summary of Contents for AST-24AI
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