97
Installation and Maintenance
Service Manual
Error
code
Malfunction name AC status Possible causes
Liquid valve temperature
sensor is ON / short-
circuited
1. Temperature sensor is not well connected or damaged;
2. The wire of temperature sensor is damaged, causing short
circuit to copper pipe or outer casing;
3. Main board of outdoor unit is damaged.
High pressure protection of
system
Cool/Dry: all loads stops operation
except indoor fan;
Heat: all loads stops operation.
1. Heat exchange of outdoor unit is too dirty, or it blocked the air
inlet/outlet;
2. Is power voltage normal; (three-phase unit)
3. Ambient temperature is too high;
4. Wiring of high pressure switch is loose or high pressure
switch is damaged;
5. The internal system is blocked; (dirt blockage, ice blockage,
oil blockage, angle valve is not completely opened)
6. Main board of outdoor unit is damaged;
7. Refrigerant is too much.
Low pressure/low system
pressure protection/
compressor low pressure
protection
Cool: compressor, outdoor fan and
indoor fan stop operation; Heat:
compressor and outdoor fan stop
operation at rst. About 1 minute
later, indoor fan stops operation; 2
minutes later, the 4-way valve stop
operation.
1. Low pressure switch is damaged;
2. Refrigerant inside the system is insufcient.
High discharge
temperature protection of
compressor
Cool/Dry: compressor and outdoor
fan stops operation, while indoor
fan operates;
Heat: all loads stops operation.
See “Overload protection of compressor , High discharge
temperature protection of compressor”
AC overcurrent protection
Cool/Dry: compressor and outdoor
fan stops operation, while indoor
fan operates;
Heat: all loads stops operation.
1. Power voltage is unstable;
2. Power voltage is too low;
3. System load is too high, which leads to high current;
4. Heat exchange of indoor unit is too dirty, or it blocked the air
inlet/outlet;
5. Fan motor operation is abnormal; the fan speed is too low or
not functioning;
6. Compressor is blocked;
7. The internal system is blocked; (dirt blockage, ice blockage,
oil blockage, angle valve is not completely opened)
8. Main board of outdoor unit is damaged.
See “AC overcurrent protection”
Mode shock/sysmte mode
shock
Load of indoor unit stops operation
(indoor fan, E-heater, swing)
Malfunction of one-to-more system; there may be two indoor
units which has set the shock mode, such as one is cooling and
the other is heating.
High temperature
prevention protection
Cool: compressor stops operation
while indoor fan operates;
Heat: all loads stops operation.
See “High temperature prevention protection; high power;
system isabnormal”
Malfunction of EEPROM
Cool/Dry: compressor stops
operation, while indoor fan
operates;
Heat: all loads stops operation.
Main board of outdoor unit is damaged.
Refrigerant-recovery mode
Cool/Dry: compressor and outdoor
fan stops operation, while indoor
fan operates.
Refrigerant recovery.
The maintenance personnel operate it when he is maintaining
the unit.
Outdoor ambient
temperature is open/short-
circuited
Cool/Dry: compressor and outdoor
fan stop operation, while indoor
fan operates;
Heat: all loads stops operation.
1. Temperature sensor is not connected well or damaged;
2. Temperature sensor wire of outdoor unit is damaged; short
circuit between the temperature sensor and copper pipe or
outer case;
3. Main board of outdoor unit is damaged;
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