68
Installation and Maintenance
Service Manual
9. Maintenance
Error
code
Malfunction name AC status Possible causes
Outdoor condenser
temperature sensor is
open/short-circuited
Cool/Dry: compressor and outdoor
fan stop operation, while indoor fan
operates;
Heat: after operating for 3mins, 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.
Module overheating
protection
Cool: compressor stops operation,
while indoor fan operates; Heat: all
loads stops operation.
1. Air inlet / air outlet of outdoor unit are blocked by lth or dirt;
2. Condenser of outdoor unit is blocked by lth or dirt;
3. IPM screw of main board is not tightened;
4. Main board of outdoor unit is damaged;
Malfunction of ambient
temperature sensor of
drive board
Cool: compressor, outdoor fan and
indoor fan stop operation; Heat:
compressor and outdoor fan stop
operation at rst; about 1min later,
indoor fan stops operation.
1. The ambient temperature sensor of the drive board is not
connected well;
2. Malfunction of the ambient temperature sensor of drive board.
DC bus voltage is too high Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
1. Measure the voltage between position L and position N on the
wiring board (XT). If it’s higher than 265 VAC, please turn on the
unit until the power voltage is decreased to the normal range;
2. If the AC input is normal, please replace the outdoor control
board.
DC bus voltage is too low Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
1. Measure the voltage between position L and position N on the
wiring board (XT). If it’s lower than 150 VAC, please turn on the
unit until the power voltage is increased to the normal range;
2. If the AC input is normal, please replace the outdoor control
board.
Charging malfunction of
capacitor
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
See “Charging malfunction of capacitor”
Malfunction of RF module Cool: compressor and outdoor fan
stop operation; Heat: compressor
and outdoor fan stop operation at
rst; about 1min later, indoor fan
stops operation.
1. The connection wire of RF module is not connected well.
2. Malfunction of RF module;
Phase current detection
circuit malfunction of
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates; Heat: compressor,
outdoor fan and indoor fan stops
operation.
The control board is damaged
Lost phase protection of
compressor
Cool: compressor and outdoor fan
stop operation; Heat: compressor
and outdoor fan stop operation at
rst; about 1min later, indoor fan
stops operation.
1. The main board of outdoor unit is damaged;
2. The compressor is damaged;
3. The connection wire of compressor is not connected well.
DC bus voltage drop
malfunction
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
The power voltage is unstable.
Current detection
malfunction of unit
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates; Heat: compressor,
outdoor fan and indoor fan stops
operation.
1. Is the complete unit lacking of refrigerant?
2. There’s malfunction for the circuit of control board of outdoor
unit. Replace the control board of outdoor unit.
4-way valve is abnormal This malfunction occurs when
the unit is heating. All loads stops
operation.
1. Power voltage is lower than AC175V;
2. Wiring terminal of 4-way valve is loose or broken;3. 4-way
valve is damaged. Replace the 4-way valve.
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