Daikin Indoor Unit Multi-Split Type Air Conditioner FVXS15NVJU

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 the power transistor test operation from the outdoor unit

Forced cooling operation ON/OFF switch pressed for 5 seconds?

Diagnose according to 6 LEDs lighting status

EV connector correctly inserted in the PCB

All EVs generate a latching sound after power cycle

Good coil generates a latching sound when mounted in the EV unit

Note: Latching sound varies depending on the valve type

Warning: Ensure the machine is powered off before starting the procedure

Disconnect the connectors of the thermistors from the PCB

Measure the resistance of each thermistor using a multimeter

Remove the PCB from the control PCB to measure the resistance when the room temperature thermistor is soldered on a PCB

Remove the thermistor and measure the resistance when the connector of indoor heat exchanger thermistor is soldered on a PCB

Sign off on the thermistor resistance check

1. Check the connection of connector.

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

3. Check motor control voltage (pins 4 - 3).

4. Check rotation command voltage output (pins 4 - 2).

5. Check rotation pulse input (pins 4 - 1).

1. Check the connection of connector.

2. Check motor power supply voltage output (pins 5 - 8).

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

Output voltage of about 5 V between pins 1 and 3

Generation of 3 pulses between pins 2 and 3 when the indoor fan motor is operating

If OK in both steps (1) and (2)