Daikin Outdoor Heat Pump RXL24UMVJU

EV connector correctly connected to the PCB

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

Continuity present 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

FTX09/12/15NMVJU(A) Fan motor wire breakdown/short circuit check

Check the connector for connection

Check if each resistance at the phases U - V and V - W is within specified range

Check the connector for connection

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

Check the connector for connection

If an abnormal stop occurs due to compressor startup failure or overcurrent output when using an inverter unit, it is difficult to judge whether the stop is caused by the compressor failure or some other failure (main PCB, power module, etc.). The inverter analyzer makes it possible to judge the cause of trouble easily and securely. Connect an inverter analyzer as a quasi-compressor instead of compressor and check the output of the inverter.

Step 1: Be sure to turn the power off.

Step 2: Install an inverter analyzer instead of a compressor.

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

(1) Remove the terminals from the compressor.

(2) Connect the terminals to the terminals of the inverter analyzer.

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 infinity or less than 1 k(omega), short circuit occurs on the main circuit.

Does the main circuit pass the short check?

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