Daikin Outdoor Unit Wall Mounted Type Air Conditioner RX20K2V1B

Warning: Disconnect the connectors of the thermistors from the PCB

Measure the resistance of each thermistor using a multimeter

When the room temperature thermistor is soldered on a PCB, remove the PCB from the control PCB

Measure the resistance of the room temperature thermistor

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

Measure the resistance of the indoor heat exchanger thermistor

Sign off on the thermistor resistance check

Warning: This check requires trained personnel with PPE!

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

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)

Upload a photo of the measured waveform

Sign off on the power supply waveforms check

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

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

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

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, a short circuit occurs on the main circuit

Sign off on the main circuit short check

Ensure the voltage of 320 + 100 V ~ 320 - 50 V is applied.

Voltage between the pins 4 - 7 (320 VDC expected)

Control voltage between the pins 3 - 4 (15 VDC expected)

Rotation command voltage between the pins 2 - 4 (0 ~ 6.5 VDC expected)

Operation off and power off after checks?

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

Warning: Ensure the voltage between (+) and (–) of the power module is about 0 V before proceeding

Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the connector, press the protrusion on the connector.

Connector disengaged successfully?

Measure resistance between the terminals of the power module and the terminals of the compressor with a multimeter.

Enter the resistance measurement

Evaluate the measurement results

Sign off on the power module check