31
Installation and Maintenance
Service Manual
8
Outdoor
discharge
temperature
sensor is open/
short-circuited
F5
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 condenser
temperature sensor and maiboard is loosened or poorly
contacted.
2. There’s short circuit due to trip-over of the parts on
maiboard.
3. Outdoor condenser temperature sensor is damaged
(Please check it by referring to the resistance table for
temperature sensor).
4. Mainboard is broken.
9
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.
10
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.
11
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.
12
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 been opened completely
）
13
Communi-
cation
malfunction
E6
During cooling operation, compressor
stops while indoor fan motor operates.
During heating operation, the
complete unit stops.
1. The communication line is not connected tightly or poorly
contacted.
Poor contact of any line may cause communication
malfunction.
2. The match between main board and display panel is
incorrect. Indoor and outdoor unit boards are matched
incorrectly.
3. Incorrect wire connection.
4. Controller is damaged.
14
Overload
malfunction
E8
The entire unit stops.
1. Indoor and outdoor heat exchanger is too dirty?
Or air inlet/outlet is blocked?
2. Fan motor is not working. Abnormal fan speed; fan
speed is too low or the fan doesn't run.
3. Compressor operates normally or not? Is there any
abnormal noise or oil leak? Casing is too hot?
4. System is blocked inside? (Dirt blockage? Ice blockage?
Oil blockage? Y-valve is not fully open?)
5. Main board temperature sensor detects wrongly.
15
Overload
protection for
compressor
H3
The entire unit stops.
1. Outdoor and indoor heat exchangers are too dirty or the
air inlet/outlet is blocked.
2. Fan motor is not working Abnormal fan speed; fan speed
is too low or the fan doesn't run.
3. Compressor doesn't work normally. Strange noise or
leakage occurs. Temperature of the shell is too high.
4. System is blocked inside(dirt block, ice block, oil block,
Y-valve not fully open).
5. High pressure switch is abnormal
6. The refrigerant is leaking and cause overheating
protection to compressor
