Daikin Outdoor Heat Pump RXL24UMVJUA

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

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

Resistance between the pins of the DB1

If the resistance is infinity or less than 1 k(omega), short circuit occurs on the main circuit.

Short circuit on the main circuit?

Sign off on the main circuit short check

Warning: Ensure operation is off and power is off before starting the procedure.

Disconnect the connector S70 or S71.

Control voltage between the pins 4 - 3

Rotation command voltage between the pins 4 - 2

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

4 rotation pulses (0 ~ 15 VDC) at the pins 4 - 1 when the fan motor is rotated 1 turn by hand.

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

Warning: This check requires trained personnel with PPE!

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

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

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

Upload a photo of the measured waveform

Sign off on the power supply waveform check

Fan motor wire breakdown/short circuit check

(1) Check the connector for connection.

(3) Check if each resistance at the phases U - V and V - W is within specified range in the table below.

(1) Check the connector for connection.

(2) Check the motor control voltage is generated (between the pins 2 - 3).

Warning: Disconnect the connector of thermistor ASSY from the PCB before proceeding

Enter the resistance value measured from the thermistor

Select the expected resistance value from the table

Does the measured resistance match the expected value?

If the measured resistance does not match the expected value, the thermistor must be replaced.

Sign off on the thermistor resistance check