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Control Specification
SiBE12-933_A
92
Function and Control
Detail
Detect Disconnection
If a 780-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 (only for heat pump model)
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 is shut down.
3.11.8 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.
3.11.9 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.
3.11.10 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.
3.11.11 Target Discharge Pipe Temperature Control
The target discharge pipe temperature is obtained from the indoor and outdoor heat exchanger
temperature, and the electronic expansion valve opening is adjusted so that the actual
discharge pipe temperature becomes close to the target discharge pipe 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.
♦
Target discharge pipe temperature
♦
Actual discharge pipe temperature
♦
Previous discharge pipe temperature
SC
SH
The target discharge pipe
temperature is set as to become the aiming SH.
The inclination does not change
depending on the operating condition.
(Supercool)
(Superheat)