Daikin Indoor Unit Floor Standing Multi-Split Type Air Conditioner FVXS12WVJU9

Warning: This procedure 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.

Warning: Ensure the voltage between (+) and (-) of the power module is about 0 V before proceeding

Disconnect the compressor harness connector from the outdoor unit PCB. Press the protrusion on the connector to disengage.

Connector disengaged successfully?

Measure resistance between the (+) or (-) terminal of the power module and the U, V, or W terminal of the compressor with a multimeter.

Enter the resistance measurement

Evaluate the measurement results

Sign off on the power module check

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

Before this check, be sure to check the main circuit for short circuit.

With the circuit breaker still on, measure the voltage according to the drawing of the model in question. Be careful never to touch any live parts.

To prevent an electrical shock, use a multimeter to check that the voltage between FU2 and DC– is 50 V or less.

The surface of the test points (DC–) may be covered with the coating. Be sure to make firm contact between the multimeter probes and the test points.

Before this check, be sure to check the main circuit for short circuit.

With the circuit breaker still on, measure the voltage according to the drawing of the model in question. Be careful never to touch any live parts.

To prevent an electrical shock, use a multimeter to check that the voltage between DC + and DC – is 50 V or less.