Daikin Indoor Unit Multi-Split Type Air Conditioner FVXS09NVJU

Warning: Ensure the voltage between (+) and (–) of the diode bridge (DB1) is about 0 V before proceeding

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 ∞ or less than 1 kΩ?

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

Sign off on the main circuit short 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)

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

When the room temperature thermistor is soldered on a PCB, remove the PCB from the control PCB to measure the resistance.

Room temperature thermistor removed from the PCB

Measure the resistance of the room temperature thermistor

When the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the thermistor and measure the resistance.

Indoor heat exchanger thermistor removed from the PCB

Measure the resistance of the indoor heat exchanger thermistor

Warning: This procedure requires trained personnel with PPE!

EV connector correctly inserted in the PCB

All EVs generate a latching sound after power cycle

If any EV does not generate a latching sound, proceed to next step

If there is no continuity between the pins, the EV coil is faulty