Daikin Indoor Unit Wall Mounted Type Air Conditioner FTX25KV1B

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

Continuity between the pins 1 - 6, 2 - 6, 3 - 6, and 4 - 6 (between the pins 1 - 5, 2 - 5, 3 - 5, 4 - 5 for the 5P connector models)

If continuity is confirmed in step 3, the outdoor unit PCB (main PCB) is not faulty

Sign off on the electronic expansion valve check

Fan motor wire breakdown / short circuit check

1. Check the connector for connection.

3. Check if each resistance at the phases U - V and V - W is 90 Ω ~ 100 Ω (between the pins; 12 - 9, and between 9 - 6).

1. Check the connector for connection.

2. Check the motor control voltage is generated (between the pins 2 - 3).

1. Check the connector for connection.

Warning: This procedure requires trained personnel with PPE!

Turn off the power before starting the procedure.

Install an inverter analyzer instead of a compressor.

Make sure the charged voltage of the built-in smoothing electrolytic capacitor drops to 10 VDC or below before carrying out the service work.

Enter the voltage of the built-in smoothing electrolytic capacitor

Connect the terminals to the terminals of the inverter analyzer.

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)

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

Enter the resistance between the pins of the DB1

Is the resistance ∞ or less than 1 kΩ?

If the resistance is ∞ or less than 1 kΩ, a short circuit occurs on the main circuit

Sign off on the main circuit short check

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

Voltage between (+) and (–) of the power module is about 0 V

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

Compressor harness connector disconnected from the outdoor unit PCB

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