Daikin Indoor Unit Multi-Split Type Air Conditioner FTXR18TVJUW

Warning: This procedure requires trained personnel with PPE!

If power is not turned off, stop the procedure and turn off the power

Is the inverter analyzer installed instead of a compressor?

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

Are the terminals (U,V,W) not touching each other?

If the terminals are touching, stop the procedure and correct the issue

Is the power transistor test operation activated from the outdoor unit?

Diagnose according to 6 LEDs lighting status

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: Ensure that the voltage between (+) and (–) of the power module is about 0 V before proceeding

Voltage between (+) and (–) of the power module is about 0 V

Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the connector, press the protrusion on the connector.

Compressor harness connector disconnected

Measure resistance between the (+) or (–) terminal of the power module and the U, V or W terminal of the compressor with a multimeter.

Enter the resistance measurement

Evaluate the measurement results

Sign off on the power module check

Voltage between (+) and (–) of the diode bridge (DB1)

If voltage is not about 0V, stop the procedure and report the issue

Resistance between the pins of the DB1

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

Short circuit on the main circuit?

Sign off on the main circuit short check

CTXG, FTXR, CTXS, FTXS, FVXS Series

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).

2. With the fan motor connector disconnected, measure the resistance between each pin, then make sure that the resistance is more than the value mentioned in the following table.