Control Specification
SiBE12-908
51
Function and Control
Detail
Detect Disconnection
If a 720-second timer for open control becomes over, 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.
When the condition of the above 1 or 2 is decided, the system stops after operating for
continuous 9 minutes.
Adjustment when the thermistor is disconnected
When compressor stop repeats specified time, the system should be down.
3.12.8 Control when frequency is changed
When the target discharge pipe temperature control is active, if the target frequency is changed
for a specified value in a certain time period, cancel the target discharge pipe temperature
control and change the target opening of the electronic expansion valve according to the shift.
3.12.9 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.
3.12.10 Oil Recovery Function
Outline
The electronic expansion valve opening in the cooling stopped room must be set as to open for
a certain time at a specified interval so that the oil in the cooling stopped room may not be
accumulated.
Detail
During cooling operation, every 1 hour continuous operation, the electronic expansion valves in
the operation stopped room must be opened by 80 pulses for specified time.
3.12.11 Target Discharge Pipe Temperature Control
Obtain the target discharge pipe temperature from the indoor and outdoor heat exchanger
temperature, and adjust the electronic expansion valve opening so that the actual discharge
pipe temperature become close to that temperature. (Indirect SH (superheating) control using
the discharge pipe temperature)
The electronic expansion valve opening and the target discharge pipe temperature are adjusted
every 20 seconds. The target discharge pipe temperature is controlled by indoor heat
exchanger temperature and outdoor heat exchanger temperature. The opening degree of the
electronic expansion valve is controlled by followings.
♦
The target discharge pipe temperature
♦
The actual discharge pipe temperature
♦
The previous discharge pipe temperature
SC
SH
Set the target discharge pipe
temperature as to become an aiming
SH.
Regard that the inclination cannot be
changed due to the operating
condition.
(Supercool)
(Superheat)
