Blue Series Troubleshooting (18K & 24K)

NO.	Malfunction Name	Display Method of Indoor Unit				Display Method of Outdoor Unit				A/C Status	Possible Causes
		Dual-8 Code Display	Indicator Display			Indicator Display
			Operation Indicator	Cooling Indicator	Heating Indicator	D40/D5	D41/D6	D42/D16	D43/D30
1	System High Pressure Protection	E1	Off 3s blink once			off	Blinking	Blinking	Blinking	During cooling and drying operation, all loads except the indoor fan stop operation. During heating operation, the entire unit stops.	Refrigerant was superabundant; Poor heat exchange (including filth blockage of heat exchanger and bad radiating environment); Ambient temperature is too high.
2	Antifreezing protection	E2	Off 3s and blink twice			On	Off	On	Off	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates.	Poor air-return in indoor unit; Fan speed is abnormal; Evaporator is dirty;
3	High discharge temperature protection of compressor	E4	Off 3s and blink 4 times			On	Off	On	Blinking	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Please refer to the service manual
4	Overcurrent protection	E5	Off 3s and blink 5 times			Off	On	Blinking	Off	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Supply voltage is unstable; Supply voltage is too low and load is too high; Evaporator is dirty;
5	Communication malfunction	E6	Off 3s and blink 6 times			Off	Off	Off	Blinking	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Please refer to the service manual
6	High temperature resistant protection	E8	Off 3s and blink 8 times			On	Off	On	On	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Please refer to the service manual
7	Internal motor (fan motor) does not operate	H6	Off 3s and blink 11 times							Internal fan motor, external fan motor, compressor and electric heater stop operation. Guid louver stops at present location.	Bad contact of DC motor feedback terminal; Bad contact of DC motor control end; Fan motor is stalling; Motor malfunction; Malfunction of main board rev detecting difficulty;
8	Malfunction protection of jumper cap	C5	Off 3s and blink 15 times							Indoor unit does not respond to the wireless remote commands.	No jumper cap inserted to main board; Jumper cap is inserted incorrectly; Jumper cap is damaged; Abnormal detecting circuit of main board;
9	Indoor ambient temperature sensor is open/short circuited	F1		Off 3s and blink once						During cooling and drying operation, indoor unit operates while other loads will stop. During heating operation the complete unit will stop operation.	Loosening or bad contact of indoor ambient temp. sensor and main board terminal; Components in main board fell down leading to short circuit; Indoor ambient temp. sensor damaged; Main board damaged;
10	Indoor evaporator temperature sensor is open/short circuited	F2		Off 3s and blink twice						AC stops operation once it reaches the set temperature. Cooling/drying: internal fan motor stops operation while other loads stop operation. Heating: AC stops operation.	Loosening or bad contact of indoor evaporator temp. sensor and main board terminal; Components in main board fell down leading to short circuit; Indoor evaporator temp. sensor damaged; Main board damaged;
11	Outdoor ambient temperature sensor is open/short circuited	F3		Off 3s and blink 3 times		Off	Off	Blinking	On	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Outdoor temperature sensor hasn't been connected well or is damaged.
12	Outdoor condenser temperature sensor is open/short circuited	F4		Off 3s and blink 4 times		Off	Off	Blinking	Off	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Outdoor temperature sensor hasn't been connected well or is damaged.
13	Outdoor discharge temperature sensor is open/short circuited	F5		Off 3s and blink 5 times		Off	Off	Blinking	Blinking	During cooling and drying operation, compressor will stop after operating for about 3 mins while indoor fan will operate. During heating operation, the complete unit will stop after operating for about 3 minutes.	Outdoor temperature sensor hasn't been connected well or is damaged; The head of temperature sensor hasn't been inserted in to the copper tube;
14	Limit/decrease frequency due to overload	F6		Off 3s and blink 6 times		On	Off	Blinking	Blinking	All loads operate normally, while operation frequency for compressor is decreased.	Please refer to the service manual
15	Decrease frequency due to overcurrent	F8		Off 3s and blink 8 times		On	On	Off	On	All loads operate normally, while operation frequency for compressor is decreased.	The input supply voltage is too low; System pressure is too high and overload;
16	Decrease frequency due to high air discharge	F9		Off 3s and blink 9 times		On	On	Off	Off	All loads operate normally, while operation frequency for compressor is decreased.	Overload or temperature is too high; Refrigerant is insufficient; Malfunction of electric expansion valve (EKV);
17	Voltage for DC bus-bar is too high	PH		Off 3s and blink 11 times		Off	On	Off	Blinking	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Measure the voltage of position L and N on the wiring board (XT). If the voltage is higher than 265V AC, turn on the units after the supply voltage is increased to the normal range. If the AC input is normal, measure the voltage of electrolytic capacitor C on control panel (AP1), if it is normal, there's a malfunction on the circuit. Please replace the control panel (AP1).
18	Zero-crossing malfunction of outdoor unit	U9		Off 3s and blink 13 times		Off	On	Blinking	On	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Replace outdoor control panel (AP1)
19	Overcurrent protection of phase current for compressor	P5		Off 3s and blink 15 times		Off	Blinking	Off	Off	During cooling and drying operation, compressor and outdoor fan stop while indoor fan operates. During heating, all loads stop.	Please refer to the service manual
20	Defrosting	H1			Off 3s and blink once