Daikin Air Conditioner RK30NMVJUA

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;

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;

Voltage between (+) and (-) of the diode bridge (DB1)

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

Resistance between the pins of the DB1

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

Sign off on the main circuit short check

Warning: Ensure that the voltage of 320 + 100 V ~ 320 - 50 V is applied

Set operation off and power off. Disconnect the connector S70 or S71

Control voltage between the pins 4 - 3

Rotation command voltage between the pins 4 - 2

Keep operation off and power off

Connect the connector S70 or S71

4 rotation pulses (0 ~ 15 VDC) at the pins 4 - 1 when the fan motor is rotated 1 turn by hand

Sign off on the rotation pulse check

Before this check, be sure to check the main circuit for short circuit

With the circuit breaker still on, measure the voltage according to the drawing of the model in question

Be careful never to touch any live parts

To prevent an electrical shock, use a multimeter to check that the voltage between FU2 and DC– is 50 V or less

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

Be sure to make firm contact between the multimeter probes and the test points;