Daikin FTX09NMVJU, Service Manual

Page: 62 / 145

Control Specification SiUS091601E
51 Functions and Control
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 is equalized.
3.11.2 Pressure Equalizing Control
When the compressor is stopped, the pressure equalizing control is activated. The electronic
expansion valve opens and the pressure is equalized.
3.11.3 Opening Limit Control
The maximum and minimum opening of the electronic expansion valve are limited.
The electronic expansion valve is fully closed when cooling operation stops, and is opened at a
fixed degree during defrosting.
3.11.4 Starting Operation Control
The electronic expansion valve opening is controlled when the operation starts, thus preventing the
superheating or liquid compression.
3.11.5 Control when the frequency changes
When the target discharge pipe temperature control is active, if the target frequency changes to a
specified value in a certain time period, the target discharge pipe temperature control is canceled
and the target opening of the electronic expansion valve is changed according to the frequency
shift.
3.11.6 High Discharge Pipe Temperature Control
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.
3.11.7 Discharge Pipe Thermistor Disconnection Control
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, operates for a specified time, and then stops.
After 3 minutes, 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 repeatedly, the system is shut down. When the compressor runs for
60 minutes without any error, the error counter is reset.
Detail Determining thermistor disconnection
When the starting control finishes, the detection timer for disconnection of the discharge pipe
thermistor (
A
seconds) starts. When the timer is over, the following adjustment is made.
1. When the operation mode is cooling
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe tempe6°C (+10.8°F) < outdoor heat exchanger temperature
09/12 class 15 class
Maximum opening (pulse) 470 480
Minimum opening (pulse) 32 52