SiBE121021_C
Control Specification
Function and Control
121
4.11 Low Hz High Pressure Limit
Outline
The upper limit of high pressure in a low Hz zone is set. The upper limit of the indoor heat
exchanger temperature is also set by the operating frequency. Zones are divided into three,
reset zone, keep zone, and drooping zone, and the frequency control is carried out according to
each zone.
Detail
Note:
Drooping: The system stops 2 minutes after staying in the drooping zone.
4.12 Electronic Expansion Valve Control
Outline
The following items are included in the electronic expansion valve control.
Electronic expansion valve is fully closed
1. Electronic expansion valve is fully closed when turning on the power.
2. Pressure equalizing control
Room Distribution Control
1. Gas pipe isothermal control
2. SC (subcooling) control
3. Liquid pipe temperature control (with all ports connected and all rooms being air-
conditioned)
4. Liquid pipe temperature control for stopped rooms
5. Dew prevention control for indoor rotor
Open Control
1. Electronic expansion valve control when starting operation
2. Electronic expansion valve control when frequency changed
3. Electronic expansion valve control for defrosting
4. Electronic expansion valve control for oil recovery
5. Electronic expansion valve control when a discharge pipe temperature is abnormally high
6. Electronic expansion valve control when the discharge pipe thermistor is disconnected
7. Electronic expansion valve control for indoor unit freeze-up protection
Feedback Control
1. Discharge pipe temperature control
50-75
class
80/90
class
A
(°C)
60
57
B
(°C)
59
56
C
(°C)
56
53
A
B
C
Highest indoor
heat exchanger
temperature
among
operating rooms
Reset zone
Drooping zone
Keep
zone
(R14587)
