Daikin Indoor Unit Multi-Split Type Air Conditioner CDXS07LVJU

Warning: This procedure requires trained personnel with PPE!

Main circuit checked for short circuit?

Warning: Never touch any live parts during the procedure.

Ensure 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 data is for reference purpose only

Room temperature thermistor removed from the PCB

Measure the resistance of the room temperature thermistor

Indoor heat exchanger thermistor removed

Measure the resistance of the indoor heat exchanger thermistor

Sign off on the thermistor resistance check

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

1. Check if the EV connector is correctly inserted in the PCB. Match the EV unit number and the connector number.

2. Turn the power off and on again, and check if all the EVs generate a latching sound.

3. If any of the EVs does not generate a latching sound in the above step 2, disconnect that 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.

4. If no EV generates a latching sound in the above step 2, the outdoor unit PCB is faulty.

5. If the continuity is confirmed in the above step 3, mount a good coil (which generated a latching sound) in the EV unit that did not generate a latching sound, and check if that EV generates a latching sound.

∗If a latching sound is generated, the outdoor unit PCB is faulty.

∗If a latching sound is not generated, the EV unit is faulty.

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 the power transistor test operation from the outdoor unit.

Forced cooling operation ON/OFF switch pressed for 5 seconds?

Diagnose according to 6 LEDs lighting status.

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 (Refer to Fig.1)?

Is there waveform disturbance near the zero-cross (Refer to sections circled in Fig.2)?

Upload a photo of the measured waveform

Sign off on the power supply waveform check