Daikin Indoor Unit Wall Mounted Type Air Conditioner FTX18WVJU9

EV connector correctly connected to the PCB

EV generates a latching sound when power is turned off and on

Continuity confirmed when connector is disconnected and checked with a multimeter

Check the continuity between the pins

Outdoor unit PCB (main PCB) is not faulty

Sign off on the electronic expansion valve check

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: 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

Center of TEMP button and OFF button on the remote controller pressed at the same time?

Warning: Ensure the voltage between (+) and (-) of the diode bridge (DB1) is about 0 V before proceeding

Enter the voltage between (+) and (-) of the diode bridge (DB1)

Is the voltage approximately 0 V?

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

Enter the resistance between the pins of the DB1

Is the resistance either infinity or less than 1 kΩ?

If resistance is not infinity or less than 1 kΩ, a short circuit occurs on the main circuit

Sign off on the main circuit short check

Ensure that the voltage is within 320 VDC

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

If NG in step 2 -> Defective PCB -> Replace the outdoor unit PCB (main PCB)