Daikin FTXS09HVJU, Service Manual

Page: 68 / 274

Control Specification (15/18/24 Class) SiUS04-904
58 Function and Control
4.12.1 Fully Closing with Power ON
Initialize the electronic expansion valve when turning on the power, set the opening position and
develop pressure equalizing.
4.12.2 Pressure Equalization Control
When the compressor is stopped, open and close the electronic expansion valve and develop
pressure equalization.
4.12.3 Opening Limit
Outline Limit a maximum and minimum opening of the electronic expansion valve.
Detail

A maximum electronic expansion valve opening : 450 pulses

A minimum electronic expansion valve opening : 54 pulses
The electronic expansion valve is fully closed in the room where cooling is stopped and is opened
with fixed opening during defrosting.
4.12.4 Starting Operation Control
Control the electronic expansion valve opening when the system is starting, and prevent the
system to be superheated or moistened.
4.12.5 High Discharge Pipe Temperature
When the compressor is operating, if the discharge pipe temperature exceeds a certain value, open
the electronic expansion valve and run the refrigerant to the low pressure side and lower discharge
pipe temperature.
4.12.6 Disconnection of the Discharge Pipe Thermistor
Outline Detect a disconnected discharge pipe thermistor by comparing the discharge pipe temperature with
the condensation temperature. If any is disconnected, open the electronic expansion valve
according to the outdoor air temperature and the operating frequency, and operate for a specified
time, and then stop.
After 3 minutes of waiting, restart the unit and check if any is disconnected. If any is disconnected
stop the system after operating for a specified time. If the disconnection is detected 4 times in
succession, the system shuts down.
Detail Detect Disconnection
If a 630-second timer for open control becomes over, and a 9-minute timer for the compressor
operation continuation is not counting time, the following adjustment must be made:
1. When the operation mode is cooling

When the discharge pipe temperature is lower than the outdoor heat exchanger temperature,
the discharge pipe thermistor disconnection must be ascertained.
2. When the operation mode is heating

When the discharge pipe temperature is lower than the max temperature of operating room heat
exchanger, the discharge pipe thermistor disconnection must be ascertained.
Adjustment when the thermistor is disconnected
When compressor stop repeats specified time, the system should be down.