Daikin Indoor Unit Wall Mounted Type Air Conditioner FTX24WVJU9

Voltage between (+) and (–) of the diode bridge (DB1)

If voltage is not about 0V, stop the procedure and report the issue

Resistance between the pins of the DB1

If the resistance is  or less than 1 k, short circuit occurs on the main circuit.

Does the main circuit have a short circuit?

Sign off on the main circuit short check

Warning: Ensure the voltage is within 320 VDC before proceeding.

Set operation off and power off. Disconnect the connector S70 or S71.

Check that the voltage between the pins 4 - 7 is 320 VDC.

Check that the control voltage between the pins 4 - 3 is 15 VDC.

Check that the rotation command voltage between the pins 4 - 2 is 0 ~ 6.5 VDC.

Keep operation off and power off. Connect the connector S70 or S71.

Check whether 4 rotation pulses (0 ~ 15 VDC) are input at the pins 4 - 1 when the fan motor is rotated 1 turn by hand.

When the fuse is melted, check the outdoor fan motor for proper function.

1. Check the connection of connector.

2. Check motor power supply voltage output (pins 4 - 7).

3. Check motor control voltage (pins 4 - 3).

4. Check rotation command voltage output (pins 4 - 2).

5. Check rotation pulse input (pins 4 - 1).

Fan motor wire breakdown/short circuit check

(1) Check the connector for connection.

Warning: Ensure the voltage between (+) and (–) of the power module is about 0 V before proceeding

Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the connector, press the protrusion on the connector.

Connector disengaged successfully?

Measure resistance between the terminals of the power module and the terminals of the compressor with a multimeter.

Enter the resistance measurement

Evaluate the measurement results

Sign off on the power module check

Warning: This procedure requires trained personnel with PPE!

Install an inverter analyzer instead of a compressor

Charged voltage of the built-in smoothing electrolytic capacitor dropped to 10 VDC or below?

Terminals removed from the compressor?

Terminals connected to the terminals of the inverter analyzer without touching each other?

Activate the power transistor test operation from the outdoor unit

Power transistor test operation activated?

Diagnose according to 6 LEDs lighting status