Daikin Indoor Unit Multi-Split Type Air Conditioner CTXG18QVJUS

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 NG in step (1) -> Defective PCB -> Replace the PCB (control PCB)

If NG in step (2) -> Defective Hall IC -> Replace the indoor fan motor

If OK in both steps (1) and (2) -> Replace the PCB (control PCB)

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).

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

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.

Check to make sure that the voltage between (+) and (–) of the diode bridge (DB1) is about 0 V before checking.

Measure the resistance between the pins of the DB1 referring to the table below.

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