Daikin Outdoor Heat Pump RX50G3V1B

Warning: This check is only for RX50/60G2V1B9, RX50/60G3V1B, RX60G4V1B models

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

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

Resistance between the pins of the DB1

Is the resistance ∞ or less than 1 kΩ?

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

Sign off on the main circuit short 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 without touching each other?

Activate the power transistor test operation from the outdoor unit.

Forced cooling operation ON/OFF button pressed for 5 seconds?

Diagnose according to 6 LEDs lighting status.

Check No.11: Power Supply Waveforms Check

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

Is the power supply waveform a sine wave (Refer to Fig.1)?

Is there waveform disturbance near the zero-cross (Refer to sections circled in Fig.2)?

Upload a photo of the measured waveform

Sign off on the power supply waveforms check

Check No.16: Make sure that the voltage of 320 is applied.

1. Set operation off and power off. Disconnect the connector S70.

2. Check that the voltage between the pins 4 - 7 is 320 VDC.

3. Check that the control voltage between the pins 3 - 4 is 15 VDC.

4. Check that the rotation command voltage between the pins 2 - 4 is 0 ~ 6.5 VDC.

5. Keep operation off and power off. Connect the connector S70.

6. Check whether 4 pulses (0 ~ 15 VDC) are input at the pins 1 - 4 when the fan motor is rotated 1 turn by hand.

When the fuse is melted, check the outdoor fan motor for proper function.

If NG in step 2 → Defective PCB → Replace the outdoor unit PCB (main PCB).

EV connector correctly connected to the PCB

EV generates a latching sound when power is turned off and on

Continuity confirmed when connector is disconnected and checked with a multimeter

Check the continuity between the pins

If there is no continuity between the pins, the EV coil is faulty

If the continuity is confirmed, the outdoor unit PCB is faulty

Sign off on the electronic expansion valve check