Daikin SUPER MULTI NX G Series Service Manual page 64

Control Specification
3.12.1 Fully Closing with Power on
The electronic expansion valve is initialized when the power is turned on. The opening position is
set and the pressure equalization is developed.
3.12.2 Pressure Equalization Control
When the compressor is stopped, pressure equalization control is activated. The electronic
expansion valve opens, and develops pressure equalization.
3.12.3 Opening Limit
Outline A maximum and minimum opening of the electronic expansion valve is limited.
 A maximum electronic expansion valve opening in the operating room: 450 pulses
Detail
 A minimum electronic expansion valve opening in the operating room: 75 pulses
The electronic expansion valve is fully closed in the room where cooling is stopped and is opened
at a fixed amount during defrosting.
3.12.4 Starting Operation Control / Changing Operation Room
Keep the electronic expansion valve from opening when the system is starting or the operating room is
changed, and to prevent the system to be from being super heated or liquid back to the compressor.
3.12.5 High Discharge Pipe Temperature
When the compressor is operating, if the discharge pipe temperature exceeds a certain value, the
electronic expansion valve opens and the refrigerant flows to the low pressure side.
This procedure lowers the discharge pipe temperature.
3.12.6 Oil Recovery Function
Outline
The electronic expansion valve opening in the cooling-stopped room must be set to open for a certain
time and at specified intervals so that the oil does not accumulate in the room where cooling has
stopped.
Detail
During cooling operation, every 1 hour of continuous operation, the electronic expansion valves in
the operation stopped room is opened by 80 pulses for specified time.
3.12.7 Gas Pipe Isothermal Control During Cooling
When units are operating in multiple rooms, the gas pipe temperature is detected and the electronic
expansion valve opening is adjusted so that the gas pipe temperature in each room becomes
equal.
 When the gas pipe temperature > the average gas pipe temperature,
 When the gas pipe temperature < the average gas pipe temperature,
The temperatures are monitored every 40 seconds.
55
→ open the electronic expansion valve in that room
→ close the electronic expansion valve in that room
SiUS12-928_A
Function and Control