Daikin Outdoor Unit Heat Pump For Split System RXS25E2V1B

Warning: Ensure the voltage between (+) and (–) of the diode bridge (DB1) is about 0 V before checking.

Enter the voltage between (+) and (–) of the diode bridge (DB1)

Measure the resistance between the pins of the DB1 referring to the table below.

Enter the 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

EV connector correctly connected to the PCB

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

Continuity confirmed when connector is disconnected and checked with a multimeter

Continuity between the pins 1 - 6, 3 - 6, 2 - 5, 4 - 5 (between the pins 1 - 6, 2 - 6, 3 - 6, 4 - 6 for the harness 5P models)

If continuity is confirmed in step 3, the outdoor unit PCB is faulty

Sign off on the electronic expansion valve check

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

Thermistors disconnected from the PCB?

Measure the resistance of the room temperature thermistor using multimeter

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

Room temperature thermistor removed from the PCB?

Measure the resistance of the room temperature thermistor

If the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the thermistor

Indoor heat exchanger thermistor removed from the PCB?

Measure the resistance of the indoor heat exchanger thermistor

RK(X)S25/35E2V1B, RK(X)S25/35G2V1B, RXS25/35L3V1B

Ensure the voltage of 320 ± 30 V is applied.

Set operation off and power off. Disconnect the connector S70 or S71.

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

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

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

Keep operation off and power off. Connect the connector S70 or S71.

Check whether 4 rotation 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.

Warning: This check requires trained personnel with PPE!

Is the power supply waveform between No. 1 and No. 2 on the terminal board a sine wave?

Upload a photo of the waveform (Fig.1)

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

Upload a photo of the waveform disturbance (Fig.2)

Sign off on the power supply waveforms check