Daikin Outdoor Unit Ceiling Mounted Cassette Type Heat Pump RX15RMVJUA

Check No.22: Make sure that the voltage between (+) and (–) of the power module is approximately 0 V before checking.

Voltage between (+) and (–) of the power module is approximately 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

Follow the procedure below to measure resistance between the terminals of the power module and the terminals of the compressor with a multimeter.

Enter the resistance measurement between the terminals of the power module and the terminals of the compressor

Evaluate the measurement results

Sign off on the power module check

Warning: This procedure requires trained personnel with PPE!

Install an inverter analyzer instead of a compressor.

Charged voltage of the built-in smoothing electrolytic capacitor dropped to 10 VDC or below?

Terminals removed from the compressor?

Terminals connected to the terminals of the inverter analyzer without touching each other?

Activate power transistor test operation from the outdoor unit.

FAN operation set using the remote controller?

Check No.20: Check to make sure that the voltage between (+) and (–) of the diode bridge (DB1) is approximately 0 V before checking.

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

Measure the resistance between the pins of the DB1 referring to the table below.

Enter the resistance between the pins of the DB1

If the resistance is  or less than 1 k, does short circuit occur on the main circuit?

Sign off on the main circuit short check

EV connector correctly connected to the PCB

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

Continuity confirmed when connector is disconnected and checked with a multimeter

Check the continuity between the pins

EV coil is not faulty if there is continuity between the pins

Outdoor unit PCB (main PCB) is faulty if continuity is confirmed

Sign off on the electronic expansion valve check

Measure the power supply waveform between No. 1 and No. 2 on the terminal block

Check if the power supply waveform is a sine wave (Fig.1)

Check if there is waveform disturbance near the zero-cross (sections circled in Fig.2)

Sign off on the power supply waveforms check