Daikin VRV X Series High-COP Type Air Conditioner RXQ40AHR

CHECK 4: Perform the following procedures prior to check.

All wiring removed from the PCB where power transistors are mounted on

Point of Measurement and Judgment Criteria

Measurement of resistance made after a lapse of 10 minutes or more

Measurement mode for analog type of multimeter

Warning: This check requires trained personnel with PPE!

Enter the high pressure reading

Is overload control conducted causing insufficient cooling capacity?

Enter the superheating degree of suction gas

Is the compressor lower in discharge pipe temperature despite of pressure loads?

Enter the subcooling degree of condensate

Is the subcooling degree of condensate high?

Sign off on the refrigerant overcharge check

Is the temperature setting of the remote controller at the lowest level in cooling mode or in test mode?

Is the air from indoor unit cool?

Is the air from outdoor unit warm?

Is the compressor operating (sound or vibration)?

Procedure for checking outdoor-outdoor unit transmission wiring for broken wires

Turn OFF the power supply to all equipment

Short circuit between the outdoor-outdoor unit terminal F1 and F2 in the 'Outdoor Unit A'

Conduct continuity checks between the transmission wiring terminal blocks F1 and F2 of the central remote controller using a multimeter

Is there continuity between the said terminal blocks?

If there is no continuity, the transmission wiring may have broken wires.

Conduct continuity checks between the transmission wiring terminal blocks F1 and F2 of the unified ON/OFF controller

Conduct continuity checks between the outdoor-outdoor unit terminal of the 'Outdoor Unit E'

Conduct continuity checks between the outdoor-outdoor unit terminal of the 'Outdoor Unit D'

CHECK 7: In case of VRV systems, the only way to judge as the shortage of refrigerant is with operating conditions due to the relationship to pressure control and electronic expansion valve control.

As information for making a judgment, refer to the information below.

Diagnosis of refrigerant shortage

1. The superheating degree of suction gas rises. Consequently, the compressor discharge gas temperature becomes higher.

2. The superheating degree of suction gas rises. Consequently, the electronic expansion valve turns open.

3. Low pressure drops to cause the unit not to demonstrate cooling capacity.;