Daikin FTKS20DVMW(L), Service Manual, Page: 80 / 228

SiENBE04-507A Control Specification
Function and Control 71
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.
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.
Detail
„ A maximum electronic expansion valve opening : 480 pulses
„ A minimum electronic expansion valve opening : 52 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 Starting Operation Control
Control the electronic expansion valve opening when the system is starting, and prevent the
system to be super heated or moistened.
3.11.5 High Temperature of the Discharge Pipe
When the compressor is operating, if the discharge pipe temperature exceeds a certain value,
open the electronic expansion valve and remove the refrigerant to the low pressure side and
lower discharge temperature.
3.11.6 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, then the system will be down.
Detail
Detect Disconnection
If the timer for open control (cooling : 13min., heating : 15min.) becomes over, and the 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 (only for heat pump model)
When the discharge pipe temperature is lower than the max temperature of indoor unit 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.