Daikin Ceiling Concealed Duct Type Heat Pump Indoor Unit FLXS35BAVMB9

Warning: This check requires trained personnel with PPE!

Is the power supply waveform between No. 1 and No. 2 on the terminal board a sine wave?

Upload a photo of the waveform (Fig.1)

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

Upload a photo of the waveform disturbance (Fig.2)

Sign off on the power supply waveforms check

1. Check the connector connection.

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

(1) Output voltage of about 5 V between pins 1 and 3.

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

If NG in step (1) => Defective PCB => Replace the PCB (control PCB).

If NG in step (2) => Defective Hall IC => Replace the fan motor.

If OK in both steps (1) and (2) => Replace the PCB (control PCB).;

EV connector correctly connected to the PCB

EV generates a latching sound when power is turned off and on again

Continuity confirmed when connector is disconnected and checked with a multimeter

Check the continuity between the pins

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

If the continuity is confirmed, the outdoor unit PCB is faulty

Sign off on the electronic expansion valve check

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

Measure the resistance of the room temperature thermistor using multimeter

If the room temperature thermistor is soldered on a PCB, remove the PCB from the control PCB to measure the resistance

Measure the resistance of the indoor heat exchanger thermistor

If the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the thermistor and measure the resistance

Sign off on the thermistor resistance 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?

Diagnose according to 6 LEDs lighting status

If all the LEDs are lit uniformly, the compressor is defective. Replace the compressor.