Daikin Air Conditioner FTX30NVJU

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;

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

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

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

Warning: Ensure the power is off before starting the procedure

Voltage between (+) and (-) of the power module

Is the voltage approximately 0V?

Disconnect the compressor harness connector from the outdoor unit PCB

Press the protrusion on the connector to disengage

Resistance between the terminals of the power module

Resistance between the terminals of the compressor

Sign off on the power module check