Daikin Outdoor Heat Pump RXN18KEVJU

Warning: Ensure the voltage between (+) and (-) of the diode bridge (DB1) is approximately 0 V before proceeding.

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

Is the voltage approximately 0 V?

Enter the resistance between the pins of the DB1

Is the resistance 'infinity' or less than 1 kW?

If the resistance is 'infinity' or less than 1 kW, a short circuit occurs on the main circuit.

Sign off on the main circuit short check

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

Voltage between (+) and (–) of the diode bridge (DB1) is approx. 0 V

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

Compressor harness connector successfully disconnected

Measure resistance between the terminals of the DB1 and the terminals of the compressor with a multi-tester.

Enter the resistance measurement

Measurement within acceptable range

Sign off on the power module check

Warning: Be sure to wait for 10 minutes or more after turning off all power supplies before disassembling work.

Disconnect the refrigerant piping.

Preparation: Remove the electrical box according to the “Removal of Electrical Box / PCBs / Swing Motors”.

Caution: If the refrigerant leaks, repair the spot of leaking, then collect all refrigerant from the unit. After conducting vacuum drying, recharge proper amount of refrigerant.

Caution: In pump-down work, be sure to stop the compressor before disconnecting the refrigerant pipe. If the refrigerant pipe is disconnected with the compressor operating and the stop valve open, air may be sucked in and may generate an over-pressure in refrigeration cycle, thus resulting in pipe rupture or accidental injury.

Place a plastic sheet under the drain pan to prevent from wetting the floor with remaining drain.

If the drain hose is embedded in the wall, disconnect the drain hose beforehand.

Carry out the removal works with 2 wrenches.

When the pipings are disconnected, protect both the openings of pipe and unit from entering of moisture.

Warning: This procedure requires trained personnel with PPE!

Install the inverter checker 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 checker without touching each other?

09/12 class: Activate power transistor test operation from indoor unit

FAN operation selected with the [MODE] button on the remote controller?

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

Thermistors disconnected from the PCB?

Measure the resistance of each thermistor using tester

Select the model of the thermistor

For the models in which the thermistor is directly mounted on the PCB, disconnect the connector for the PCB and measure.

Thermistor disconnected from the PCB for direct mounted models?

Measure the resistance of the directly mounted thermistor

Sign off on the thermistor resistance check