Daikin Air Conditioner RK30NMVJU

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

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

Check to make sure that the voltage between (+) and (–) of the diode bridge (DB1) is approximately 0 V before checking

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

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

Make sure that the voltage of 320 + 100 V ~ 320 - 50 V is applied

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

Check that the voltage between the pins 4 - 7 is 320 VDC

Check that the control voltage between the pins 4 - 3 is 15 VDC

Check that the rotation command voltage between the pins 4 - 2 is 0 ~ 6.5 VDC

Keep operation off and power off

Connect the connector S70 or S71

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

Warning: This check requires trained personnel with PPE!

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

Is the power supply waveform a sine wave?

Is there waveform disturbance near the zero-cross?

Upload a photo of the measured waveform

Sign off on the power supply waveforms check