Daikin Wall-Mounted Indoor Unit CTXS07JVJU

Conduct the followings to check the outdoor electronic expansion valve (EV).

1. Check to see 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 to see if all the EVs generate latching sound.

3. If any of the EVs does not generate latching sound in the above step 2, disconnect that connector and check the continuity using a tester.

Check the continuity between the pins 1 - 6 and 3 - 6, and between the pins 2 - 5 and 4 - 5. If there is no continuity between the pins, the EV coil is faulty.

4. If no EV generates 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 latching sound) in the EV unit that did not generate latching sound, and check to see if that EV generates latching sound.

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

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

Warning: This procedure requires trained personnel with PPE!

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

Upload a photo of the measured waveform

Is the power supply waveform a sine wave (Refer to Fig.1)?

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

Sign off on the power supply waveform check

Warning: Ensure that the voltage between (+) and (–) of the power module (PM1) is approx. 0 V before proceeding.

Voltage between (+) and (–) of the power module (PM1) is approx. 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?

Measure resistance between the terminals of the power module and the terminals of the compressor with a multi-tester.

Enter the resistance measurement

Evaluate the measurement results

Sign off on the power module check

With the power on, operation off, and the connector connected, check the following

Output voltage of about 5 V between pins 1 and 3

Generation of 3 pulses between pins 2 and 3 when the fan motor is operating

Control voltage between the pins 3 - 4

Rotation command voltage between the pins 2 - 4

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