Daikin Indoor Unit Ceiling Mounted Cassette Type Heat Pump FFQ09Q2VJU

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

Check if the power supply waveform is a sine wave (Fig.1)

Check if there is waveform disturbance near the zero-cross (sections circled in Fig.2)

Sign off on the power supply waveforms check

Check No.20: Check to make sure that the voltage between (+) and (–) of the diode bridge (DB1) is approximately 0 V before checking.

Enter the voltage between (+) and (–) of the diode bridge (DB1)

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

Enter the resistance between the pins of the DB1

Is the resistance is  or less than 1 k?

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

Sign off on the main circuit short 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 power transistor test operation from the outdoor unit

FAN operation set using the remote controller?

Check No.16: Make sure that the voltage is within 320 VDC.

1. Set operation off and power off. Disconnect the connector S70 or S71.

2. Check that the voltage between the pins 4 - 7 is 320 VDC.

3. Check that the control voltage between the pins 4 - 3 is 15 VDC.

4. Check that the rotation command voltage between the pins 4 - 2 is 0 ~ 6.5 VDC.

5. Keep operation off and power off. Connect the connector S70 or S71.

6. Check whether 4 rotation pulses (0 ~ 15 VDC) are input at the pins 4 - 1 when the fan motor is rotated 1 turn by hand.

When the fuse is melted, check the outdoor fan motor for proper function.

If NG in step 2 -> Defective PCB -> Replace the outdoor unit PCB (main PCB).

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

Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the connector, press the protrusion on the connector.

Measure resistance between the terminals of the power module

Measure resistance between the terminals of the compressor

Evaluate the measurement results

Sign off on the power module check