Daikin Outdoor Unit Multi-Split Type Air Conditioner 2MXS18NMVJUA

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.

Warning: Disconnect the connectors of the thermistors from the PCB before proceeding

Thermistors disconnected from the PCB

Resistance of room temperature thermistor

Note: If the room temperature thermistor is soldered on a PCB, remove the PCB from the control PCB to measure the resistance

Resistance of indoor heat exchanger thermistor

Note: If the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the thermistor and measure the resistance

Sign off on the thermistor resistance check

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?

Be careful not to let the terminals (U,V,W) touch each other. Otherwise, high voltage is applied.

Power transistor test operation activated from the outdoor unit?

Diagnose according to 6 LEDs lighting status.

1. Check the connector connection.

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

(1) Output voltage of about 5 V between pins 1 and 3.

(2) 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).;

Conduct the following to check the electronic expansion valve (EV).

1. Check if the EV connector is correctly inserted in the PCB. Match the EV unit number and the connector number.

2. Turn the power off and on again, and check if all the EVs generate a latching sound.

3. If any of the EVs does not generate a latching sound in the above step 2, disconnect that 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.

4. If no EV generates a latching sound in the above step 2, the outdoor unit PCB is faulty.

5. If the continuity is confirmed in the above step 3, mount a good coil (which generated a latching sound) in the EV unit that did not generate a latching sound, and check if that EV generates a latching sound.

∗If a latching sound is generated, the outdoor unit PCB is faulty.

∗If a latching sound is not generated, the EV unit is faulty.