Daikin Air Conditioner RK30NMVJU

Conduct the following to check the electronic expansion valve (EV)

Check if the EV connector is correctly connected to the PCB

Turn the power off and on again, and check to see if the EV generates a latching sound

If the EV does not generate a latching sound in the above step 2, disconnect the connector and check the continuity using a multimeter

Check the continuity between the pins 5 - 1, 5 - 2, 5 - 3, 5 - 4. If there is no continuity between the pins, the EV coil is faulty

If the continuity is confirmed in step 3, the outdoor unit PCB (main PCB) is faulty;

Check the connection of connector

Check the motor power supply voltage output

Check the motor control voltage

Check the rotation command voltage

Sign off on the connector output check

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

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

Activate power transistor test operation from the indoor unit;

Warning: This procedure requires trained personnel with PPE!

Main circuit checked for short circuit?

Warning: Never touch any live parts during the procedure.

Note: The surface of the test points (DC–) may be covered with the coating.

Firm contact between the multimeter probes and the test points?

Sign off on the capacitor voltage check

Warning: Disconnect the connectors of the thermistors from the PCB before proceeding

Thermistors disconnected from the PCB

Measure the resistance of each thermistor using a multimeter

Note: The room temperature thermistor is soldered on the PCB

Connector to the control PCB disconnected before measuring the resistance

If the connector of indoor heat exchanger thermistor is soldered on the PCB, remove the thermistor

Thermistor removed from the PCB

Measure the resistance of the removed thermistor

Sign off on the thermistor resistance check