Daikin F-Series, Service Manual

Page: 105 / 355

Control Specification SiBE12-713
94 Function and Control
3.11.1 Fully Closing with Power ON
Initialize the electronic expansion valve when turning on the power, set the opening position and
develop pressure equalizing.
The electronic expansion valves are closed further with 720 pulse, and then opened with 150
pulse.
3.11.2 Pressure Equalization Control
When the compressor is stopped, open and close the electronic expansion valve and develop
pressure equalization.
3.11.3 Opening Limit
Outline Limit a maximum and minimum opening of the electronic expansion valve in the operating room.
Detail
Š
A maximum electronic expansion valve opening in the operating room: 450 pulses
Š
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 with fixed opening during defrosting.
3.11.4 Gas Pipe Isothermal Control During Cooling
When the units are operating in multiple rooms, detect the gas piping temperature and correct
the electronic expansion valve opening so that the temperature of the gas pipe in each room
becomes identical.
Š
When the gas pipe temperature > the average gas pipe temperature,
→
open the electronic expansion valve in that room
Š
When the gas pipe temperature < the average gas pipe temperature,
→
close the electronic expansion valve in that room
The temperatures are monitored every 40 seconds.
3.11.5 SC Control
Outline Heat Pump Only
Detect the temperature of liquid pipe and heat exchanger of the rooms and compensate the
electronic expansion valve opening so that the SC of each room becomes the target SC.
Š
When the actual SC is > target SC, open the electronic expansion valve of the room.
Š
When the actual SC is < target SC, close the electronic expansion valve of the room.
Detail Start Functioning Conditions
After finishing the open control (810 seconds after the beginning of the operation), control all the
electronic expansion valve in the operating room.
Determine Electronic Expansion Valve Opening
Adjust the electronic expansion valve so that the temperature difference between the maximum
heat exchanger temperature of connected room and the temperature of liquid pipe thermistor
becomes constant.
3.11.6 Starting Operation Control / Changing Operation Room
Control the electronic expansion valve opening when the system is starting or the operating
room is changed, and prevent the system to be super heated or moistened.