Daikin FDMQ12RVJU, Service Manual

Page: 189 / 242

SiUS091601EA Check
Part 6 Service Diagnosis 184
8.3 Power Supply Waveform Check
Check No.11
Measure the power supply waveform between No. 1 and No. 2 on the terminal strip, and check the
waveform disturbance.
 Check if the power supply waveform is a sine wave (Fig.1).
 Check if there is waveform disturbance near the zero-cross (sections circled in Fig.2).
8.4 Electronic Expansion Valve Check
Check No.12
Conduct the following to check the electronic expansion valve (EV).
1. Check if the EV connector is correctly connected to the PCB.
2. Turn the power off and on again, and check if the EV generates a latching sound.
3. If the EV does not generate a latching sound in step 2, disconnect the connector and check the
continuity using a multimeter.
4. Check the continuity between the pins 5 - 1, 5 - 2, 5 - 3, 5 - 4 (between the pins 6 - 1, 6 - 2, 6 - 3,
and 6 - 4 for the 6P connector models). If there is no continuity between the pins, the EV coil is
faulty.
5. If the continuity is confirmed in step 3, the outdoor unit PCB (main PCB) is faulty.
[Fig.1] [Fig.2]
(R1736)
(R1444)
Harness 5P
5P Connector
Check
S20
5 - 1
5 - 2
5 - 3
5 - 4
1 2 3 4 5
(R23663)
Harness 5P
6P Connector
(5)
Check S20
6 - 1
6 - 2
6 - 3
6 - 4
1 2 3 4 5 6
(R23593)