Daikin Outdoor Unit for Multi-Split System 3MXS24JVJU

Check the connection of connector

Check motor power supply voltage output (pins 4 - 7)

Check motor control voltage (pins 4 - 3)

Check rotation command voltage output (pins 4 - 2)

Check rotation pulse input (pins 4 - 1)

Sign off on the fan motor connector check

Remove the sound blanket (top upper)

The sound blanket is fragile. Carefully pass the discharge pipe through it.

Remove the screw from the partition plate (1) and push the plate to the left slightly for easy work

Remove the sound blanket (outer)

The sound blanket is fragile. Carefully pass the discharge pipe through it.

Remove the sound blanket (top inner)

The sound blanket is fragile. Carefully pass the discharge pipe through it.

Open the sound blanket (inner) and pass it through the part of the mufflers

Warning: This procedure requires trained personnel with PPE!

Install the inverter checker 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 checker without touching each other?

Activate the power transistor test operation from the outdoor unit

Pressed the forced operation [ON/OFF] switch for 5 seconds?

Diagnose according to 6 LEDs lighting status

Warning: Disconnect the connectors of the thermistors from the PCB before proceeding

Thermistors disconnected from the PCB?

Measure the resistance of each thermistor using tester

Note: The relationship between normal temperature and resistance is shown in the table and the graph below

The room temperature thermistor is directly mounted on the display PCB. Remove the display PCB from the control PCB to measure the resistance.

Display PCB removed from the control PCB?

Measure the resistance of the room temperature thermistor

When the indoor heat exchanger thermistor is soldered on the PCB, remove the thermistor and measure the resistance.

Indoor heat exchanger thermistor removed from the PCB?

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.