Daikin Air Conditioner RX30NMVJUA

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

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

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

Measure the resistance between the pins of the DB1

Enter the resistance between the pins of the DB1

Is the resistance less than 1 kOhm?

If the resistance is less than 1 kOhm, a short circuit occurs on the main circuit

Sign off on the main circuit short check

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

Thermistors disconnected from the PCB

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

Indoor heat exchanger thermistor removed

Resistance of the indoor heat exchanger thermistor

Sign off on the thermistor resistance check

Warning: This procedure requires trained personnel with PPE!

If power is not turned off, stop the procedure and turn off the power

Inverter analyzer installed instead of compressor?

Ensure the charged voltage of the built-in smoothing electrolytic capacitor drops to 10 VDC or below before proceeding

Enter the charged voltage of the built-in smoothing electrolytic capacitor

Power transistor test operation activated from the indoor unit?

Sign off on the inverter analyzer check