Daikin Outdoor Heat Pump RXL09QMVJU

EV connector correctly connected to the PCB

Did the EV generate a latching sound after power cycle

Continuity confirmed using a multimeter after disconnecting the connector

Check the continuity between the pins

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 within specified range in the table below.

(1) Check the connector for connection.

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

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.

Short circuit on the main circuit?

Sign off on the main circuit short check

Warning: Ensure that 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

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