Daikin split air conditioner troubleshooting

Diagnostics of an air conditioner is the first thing, which one needs to do before its maintenance or repairs. Daikin air conditioner troubleshooting system will help you here. This procedure allows to reveal breakdowns and malfunctions in a system. It will allow the engineer to quickly remove malfunction.


The following incidents do not indicate a malfunctioning air conditioner and have explanations. The air conditioner can continue to operate.

Operation does not start soon.

• When “ON/OFF” button was pressed soon after

operation was stopped.

• When the mode was reselected.
• This is to protect the air conditioner.

You should wait for about 3 minutes.
Hot air does not fl ow out soon after the

start of HEAT operation.
• The air conditioner is warming up. You should wait for 1 to 4 minutes.

(The system is designed to start discharging air only after it has reached a certain

The HEAT operation stops suddenly and

a fl owing sound is heard.
• The system is taking away the frost on the outdoor unit.

You should wait for about 4 to 12 minutes.
The outdoor unit emits water or steam.In HEAT operation

• The frost on the outdoor unit melts into water or steam when the air conditioner is in

defrost operation.

In COOL or DRY operation

• Moisture in the air condenses into water on the cool surface of outdoor unit piping and

Mist comes out of the indoor unit.This happens when the air in the room is cooled into mist by the cold airfl ow

during COOL operation.

This is because the air in the room is cooled by the heat exchanger and

becomes mist during defrost operation.
The indoor unit gives out odor.This happens when smells of the room, furniture, or cigarettes are absorbed

into the unit and discharged with the airfl ow.

If this happens, it is recommended to have the indoor unit washed by a

technician. Consult the service shop where you purchased the air conditioner.
The outdoor fan rotates while the air

conditioner is not in operation.
After operation is stopped

• The outdoor fan continues rotating for another 60 seconds for system protection.

While the air conditioner is not in operation

• When the outdoor temperature is very high, the outdoor fan starts rotating for system

Operation stopped suddenly.

(OPERATION lamp is on.)
• For system protection, the air conditioner may stop operating on a sudden large voltage

fl uctuation.

It automatically resumes operation in about 3 minutes.
No remote controller signals are


Remote controller sensitivity is low.

Display is low in contrast or blacked out.

Display runs out of control.
• The batteries are dying and the remote controller is malfunctioning. Replace all the

batteries with new size batteries, AAA.LR03 (alkaline). For details, refer to set the batteries

of this manual.
Possible sounds.Flowing water

• Generated because the refrigerant in the air conditioner is fl owing.

• This is a pumping sound of the water in the air conditioner and heard when the water is

pumped out from the air conditioner in cooling or drying operation.

• The refrigerant fl ows in the air conditioner even if the air conditioner is not working when

the indoor units in other rooms are in operation.


• Generated when the fl ow of the refrigerant in the air conditioner is switched over.


• Generated when the size of the air conditioner slightly expands or shrinks as a result of

temperature changes.

Please check again before calling a repair person.

The air conditioner does not operate.

(OPERATION lamp is off.)
• Is a breaker off or a fuse blown?

• Is there a power failure?

• Are batteries set in the remote controller?

• Is the timer setting correct?
Cooling (Heating) effect is poor.• Are the air fi lters clean?

• Is there anything to block the air inlet or the outlet of the indoor and the outdoor units?

• Is the temperature setting appropriate?

• Are the windows and doors closed?

• Are the airfl ow rate and the airfl ow direction set appropriately?
Operation stopped suddenly.

(OPERATION lamp fl ashes.)
• Are the air fi lters clean?

• Is there anything to block the air inlet or the outlet of the indoor and the outdoor units?

• Clean the air fi lters or take all obstacles away and turn the breaker off. Then turn it on

again and try operating the air conditioner with the remote controller. If the lamp still

fl ashes, call the service shop where you purchased the air conditioner.

• Are operation modes all the same for indoor units connected to outdoor units in the multi


If not, set all indoor units to the same operating mode and confi rm that the lamps fl ash.

Moreover, when the operating mode is in AUTO, set all indoor unit operating modes to

COOL or HEAT for a moment and check again that the lamps are normal.

If the lamps stop fl ashing after the above steps, there is no malfunction.
An abnormal functioning happens during

• The air conditioner may malfunction with lightning or radio waves. Turn the breaker off,

turn it on again and try operating the air conditioner with the remote controller.
The louvers do not immediately swing.

The louvers move soon after startup.
• The air conditioner is adjusting the louvers position. The louvers will start moving soon.

If one of the following symptoms occurs, Turn the breaker off and call the service shop..

The power cord is abnormally hot or damaged.

An abnormal sound is heard during operation.

The safety breaker, a fuse, or the ground leakage breaker cuts off the operation frequently.

A switch or a button often fails to work properly.

There is a burning smell.

Water leaks from the indoor unit.

Daikin split air conditioner error codes

U0Refrigerant shortage
U2Drop voltage or main circuit overvoltage
U4Failure of transmission (between indoor unit and outdoor unit)
Indoor unitA1Indoor pcb defectiveness
A5High pressure control or freeze-up protector
A6Fan motor fault
C4Faulty heat exchanger temperature sensor
C9Faulty suction air temperature sensor
Outdoor unitEACooling-heating switching error
E5Ol started
E6Faulty compressor start up
E7Dc fan motor fault
E8Overcurrent input
F3High temperature discharge pipe control
H6Operation halt due to faulty position detection sensor
H8Dc current sensor fault
H9Faulty suction air temperature sensor
J3Faulty discharge pipe temperature sensor
J6Faulty heat exchanger temperature sensor
L4High temperature at inverter circuit heatsink
L5Output overcurrent
P4Faulty inverter circuit heatsink temperature sensor