Daikin Outdoor Unit Cold Climate Multi-Split Type Air Conditioner 2MXL18WMVJU9

Warning: This procedure requires trained personnel with PPE!

Control voltage between the pins 3 - 4

Rotation command voltage between the pins 2 - 4

Pulses output at the pins 1 - 4 when the fan motor is rotated 1 turn by hand

Is the outdoor fan motor functioning properly?

If NG in step 2 or 4, select the defective part

If OK in both steps 2 and 4, select the part to replace

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 procedure requires trained personnel with PPE!

Main circuit checked for short circuit?

Warning: Never touch any live parts during the procedure.

Is the voltage between FU2 and DC– 50 V or less?

Ensure firm contact between the multimeter probes and the test points.

Is the voltage between DC + and DC – 50 V or less?

Sign off on the capacitor voltage check

Conduct the followings 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 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 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 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.

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

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

If the resistance is infinity or less than 1 k, short circuit occurs on the main circuit.

2. Remove the top plate (10 screws).

3. Remove the right side plate (6 screws).

4. Remove the front plate (1 screw).

The front plate is heavy, so take care.