Daikin Indoor Unit Wall Mounted Type FTXJ20MV1BS

Check the connection of connector

Check the motor power supply voltage output (pins 4 - 7)

Check the motor control voltage (pins 4 - 3)

Check the rotation command voltage (pins 4 - 2)

Check the rotation pulse (pins 4 - 1)

Sign off on the fan motor connector output check

Warning: This check requires trained personnel with PPE!

Voltage between (+) and (–) of the diode bridge (DB1)

If voltage is not approximately 0 V, stop the procedure and report the issue

Resistance between the pins of the DB1

If the resistance is ∞ or less than 1 kΩ, short circuit occurs on the main circuit.

Main circuit short check passed?

Sign off on the main circuit short check

1. Check that the control voltage between the pins 10 - 11 is 15 VDC.

2. Check if the Hall IC generates the rotation pulse (0 ~ 15 VDC) 4 times between the pins 10 - 12, 10 - 13, when the fan motor i/s manually rotated once.

Make sure that the voltage of 320 ± 30 V is applied.

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

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

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

EV connector correctly connected to the PCB

Does the EV generate a latching sound when power is turned off and on again?

Continuity confirmed using a multimeter after disconnecting the connector if EV does not generate a latching sound

Check the continuity between the pins

EV coil is not faulty if there is continuity between the pins

Outdoor unit PCB is not faulty if continuity is confirmed in step 3

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

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