Daikin Ducted Type Indoor Unit FDBT24PUV2S

Set operation OFF and power OFF. Disconnect the connector.

Keep operation OFF and power OFF. Connect the connector.

2 pulses (0 and 5 VDC) are output 4 times at the pins 1 - 4 when the fan motor is rotated 1 turn by hand.

If NG in steps 2 and 3 Defective PCB

If NG in step 5 Defective Hall IC

Replace the outdoor unit fan motor.

Warning: Disconnect the thermistor from the PCB before proceeding

Thermistor disconnected from the PCB

Upload a photo of the table with the measured values

Check if the measured values correspond with the values in the table

Sign off on the thermistor check

Warning: Do not touch the energized part (high voltage part) for at least 10 minutes after the power is turned OFF.

Be sure to touch the earth terminal with a hand to release static electricity from the body (to prevent PCB from being damaged).

Measurements at the following spots and confirm that residual electric charge of the power transistor is DC 50V or less.

Confirm that the outdoor unit fan has stopped

Remove the wire connecting the power transistor and the compressor. Remove it from the compressor terminal side.

During this work, be careful not to deform. Faston terminal at the end of the relay wire.

Using an analog tester, measure resistance and fill in the blanks in the following table.

In case of unbalanced resistance for one of the 3 phases in each table (when the resistance value is equal to 5 times or more than the other resistance values), the power transistor is broken.

In normal cases, each phase shows a similar resistance value.

Diagnosis of inadequate refrigerant in cooling operation

Suction superheated degree increases due to refrigerant shortage

Decreased evaporator capacity caused by refrigerant shortage

Compressor frequency decreases despite a large difference between temperature set by the remote controller and suction air temperature

Electronic expansion valve remains fully open and suction superheated degree further increases

Diagnosis of inadequate refrigerant in heating operation

Suction superheated degree increases due to refrigerant shortage

Compressor frequency decreases because suction superheated degree is controlled to prevent oil to the outdoor unit heat exchanger from being retained

Evaporator capacity and compressor frequency decrease despite a large difference between temperature set by the remote controller and suction air temperature

Warning: High pressure checks should be performed by trained personnel only!

Enter the current pressure level

Is the pressure level above the normal range?

If the pressure level is above the normal range, proceed with the following checks

Check if the condenser side is causing the high pressure

Describe the condition of the condenser side

Sign off on the high pressure check