Daikin J Series Service Manual page 48

Control Specification
3.11.1 Fully Closing with Power ON
The electronic expansion valve is initialized when turning on the power. The opening position is
set and the pressure equalization is developed.
3.11.2 Pressure Equalization Control
When the compressor is stopped, the pressure equalization control is activated. The electronic
expansion valve opens, and develops the pressure equalization.
3.11.3 Opening Limit
Outline A maximum and minimum opening of the electronic expansion valve are limited.
Detail
The electronic expansion valve is fully closed when cooling operation stops, and is opened with
fixed opening during defrosting.
3.11.4 Starting Operation Control
The electronic expansion valve opening is controlled when the operation starts, and prevents
the superheating or liquid compression.
3.11.5 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 runs to the low pressure side. This
procedure lowers the discharge pipe temperature.
3.11.6 Disconnection of the Discharge Pipe Thermistor
Outline The disconnection of the discharge pipe thermistor is detected by comparing the discharge pipe
temperature with the condensation temperature. If the discharge pipe thermistor is
disconnected, the electronic expansion valve opens according to the outdoor temperature and
the operation frequency, and operates for a specified time, and then stops.
After 3 minutes of waiting, the operation restarts and checks if the discharge pipe thermistor is
disconnected. If the discharge pipe thermistor is disconnected, the system stops after operating
for a specified time.
If the disconnection is detected 5 times in succession, then the system is shut down. When the
compressor runs for 60 minutes without any error, the error counter is reset.
Detail When the starting control (cooling : 10 seconds, heating : 120 seconds) finishes, the detection
timer for disconnection of the discharge pipe thermistor ( 810 seconds) starts. When the timer is
over, the following adjustment is made.
1. When the operation mode is cooling
2. When the operation mode is heating
Adjustment when the thermistor is disconnected
When the disconnection is ascertained, the compressor continues operation for 9 minutes and
then stops.
When the compressor stops repeatedly, the system is shut down.
38
Maximum opening : 480 pulse
Minimum opening : 52 pulse
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C < outdoor heat exchanger temperature
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C < indoor heat exchanger temperature
SiBE041012
Function and Control