Daikin Wall Mounted Type Indoor Unit FTXS25J2V1B

EV connector correctly inserted in the PCB

All EVs generate latching sound after power cycle

Continuity between pins 1 - 6 and 3 - 6

Continuity between pins 2 - 5 and 4 - 5

Good coil generates latching sound when mounted in EV unit

Note: Latching sound varies depending on the valve type

Warning: Operating with a defective electronic expansion valve may cause problems

Sign off on the electronic expansion valve check

Output voltage between pins 1 and 3

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

If NG in step 1 or 2, identify the defective part

If OK in both steps 1 and 2, replace the PCB

Warning: This procedure requires trained personnel with PPE!

Enter the power supply waveform measurement between No. 1 and No. 2 on the terminal board

Is the power supply waveform a sine wave as shown in Fig.1?

Is there waveform disturbance near the zero cross as shown in the sections circled in Fig.2?

Upload a photo of the measured waveform

Sign off on the power supply waveform check

Check the connection of connector

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

Check motor control voltage (pins 4 - 3)

Check rotation command voltage output (pins 4 - 2)

Check rotation pulse input (pins 4 - 1)

Sign off on the fan motor connector check

Disconnect the connectors of the thermistors from the PCB

Thermistors disconnected successfully

Measure the resistance of each thermistor using tester

Check the relationship between normal temperature and resistance

For models with thermistor directly mounted on the PCB, disconnect the connector for the PCB and measure

Thermistor disconnected successfully

Measure the resistance of the thermistor