Daikin Outdoor Unit Cold Climate Multi-Split Type Air Conditioner 2MXLH18WVJU9

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?

Warning: Be careful not to let the terminals (U,V,W) touch each other. Otherwise, high voltage is applied.

Power transistor test operation activated from the outdoor unit?

Diagnose according to 6 LEDs lighting status.

Warning: This procedure requires trained personnel with PPE!

Voltage of 320 ± 30 V is applied

Set operation OFF and power OFF. Disconnect the connector S70.

Voltage between the pins 4 - 7 is 320 VDC

Control voltage between the pins 3 - 4

Control voltage between the pins 3 - 4 is 15 VDC

Rotation command voltage between the pins 2 - 4

Warning: This check requires trained personnel with PPE!

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

Is the power supply waveform a sine wave?

Is there waveform disturbance near the zero-cross?

Sign off on the power supply waveform check

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.

EV connector correctly inserted in the PCB

Match the EV unit number and the connector number

All EVs generate latching sound after power cycle

If any EV does not generate latching sound, proceed to next step

If there is no continuity between the pins, the EV coil is faulty