Daikin Outdoor Cooling/Heating Unit REYQ96TATJU

Overload control causing insufficient cooling capacity

Superheated degree of suction gas

Compressor lower in discharge pipe temperature despite of pressure loads

In heating, the temperature of discharge air through the subcooled section becomes lower

Superheated degree of suction gas

Details of compressor capacity control while in cooling, refer to Compressor PI control

The low pressure protection control includes low pressure protection control and hot gas bypass control

In cooling, the indoor unit electronic expansion valve is used for superheated degree control

In heating, the outdoor unit electronic expansion valve is used for superheated degree control of outdoor unit heat exchanger

Enter the high pressure reading

Did the system pass the pressure check?

Warning: This procedure requires trained personnel with PPE!

Check Electronic Expansion Valve Coil

Remove the connector for electronic expansion valve (X7A) from PCB

Measure the resistance value between pins

No continuity between White and Yellow

Resistance value between White and Orange

Resistance value between White and Red

Resistance value between Yellow and Blue

Resistance value between Yellow and Brown

Check for High Pressure in cooling

Check for High Pressure in heating

Check for broken wire of the relay wire (p.299)

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

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

Check Fan Motor Connector (Power Supply Cable) (p.300)

Check Fan Motor Connector (Signal Cable) (p.300)

Superheating temperature control in cooling is conducted by indoor unit electronic expansion valve

Superheating temperature control in heating is conducted by outdoor unit electronic expansion valve (main)

Judgement criteria of superheat operation:

Discharge gas superheated degree

Is the suction gas superheated degree 10°C (50°F) and over?

Is the discharge gas superheated degree 45°C (113°F) and over, except immediately after compressor starts up or is running under drooping control?

Additional notes on the superheat operation check

Sign off on the superheat operation check