Daikin Air Conditioner FTX30NVJU

Voltage applied (320 + 100 V ~ 320 - 50 V)

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

Voltage between the pins 4 - 7 (320 VDC)

Control voltage between the pins 4 - 3 (15 VDC)

Rotation command voltage between the pins 4 - 2 (0 ~ 6.5 VDC)

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

Rotation pulses (0 ~ 15 VDC) at the pins 4 - 1 when the fan motor is rotated 1 turn by hand

Sign off on the rotation pulse check

Warning: This procedure requires trained personnel. Always ensure power is off before starting.

Inverter analyzer installed instead of compressor?

Note: Ensure the charged voltage of the built-in smoothing electrolytic capacitor drops to 10 VDC or below before carrying out the service work.

Enter the charged voltage of the built-in smoothing electrolytic capacitor

Charged voltage dropped to 10 VDC or below?

Power transistor test operation activated from the indoor unit?

Upload a photo of the inverter analyzer setup

Sign off on the inverter analyzer check

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

Thermistors disconnected from the PCB

Measure the resistance of each thermistor using a multimeter

Note: The room temperature thermistor is soldered on the PCB

Connector to the control PCB disconnected before measuring the resistance

If the connector of indoor heat exchanger thermistor is soldered on the PCB, remove the thermistor

Thermistor removed from the PCB

Measure the resistance of the removed thermistor

Sign off on the thermistor resistance check

Check the connection of connector

Check the motor power supply voltage output

Check the motor control voltage

Check the rotation command voltage

Sign off on the connector output check

Conduct the following to check the electronic expansion valve (EV)

Check if the EV connector is correctly connected to the PCB

Turn the power off and on again, and check to see if the EV generates a latching sound

If the EV does not generate a latching sound in the above step 2, disconnect the connector and check the continuity using a multimeter

Check the continuity between the pins 5 - 1, 5 - 2, 5 - 3, 5 - 4. If there is no continuity between the pins, the EV coil is faulty

If the continuity is confirmed in step 3, the outdoor unit PCB (main PCB) is faulty;