Basic Control
Si18-525B
108
Function
2.
Basic Control
2.1
Normal Operation
Cooling Operation
Heating Operation
Heating operation is not functional at an outdoor air temperature of 30
°
CDB or more.
Actuator
Operation
Remarks
Compressor
Compressor PI control
Used for high pressure protection control, low
pressure protection control, discharge pipe
temperature protection control, compressor
operating frequency upper limit control with
inverter protection control, dew prevention control,
and freeze-up protection control.
Outdoor unit fan
Cooling fan control
Four way valve
OFF
Main electronic expansion valve (EV1)
2000 pls
Subcooling electronic expansion valve
(EV2)
PI control
Hot gas bypass valve (SVP)
OFF
This valve turns on with low pressure protection
control.
Receiver gas discharging valve (SVG)
OFF
This valve turns on with dew prevention control.
BP unit electronic expansion valve
(operating room)
SH control
BP unit electronic expansion valve
(stopping room)
0 pls
Actuator
Operation
Remarks
Compressor
Compressor PI control
Used for high pressure protection control, low
pressure protection control, discharge pipe
temperature protection control, and compressor
operating frequency upper limit control with
inverter protection control.
Outdoor unit fan
STEP8
The fan step changes to STEP1 with high pressure
> 3.2MPa.
Four way valve
ON
Main electronic expansion valve (EV1)
PI control
Subcooling electronic expansion valve
(EV2)
0 pls
The opening of this valve changes with high
pressure > 3.2MPa.
Hot gas bypass valve (SVP)
OFF
This valve turns on with low pressure protection
control.
Receiver gas discharging valve (SVG)
OFF
—
BP unit electronic expansion valve
(operating room)
SC control
BP unit electronic expansion valve
(stopping room)
80 pls
The opening of this valve changes with insufficient
gas control.
Summary of Contents for D-Series
Page 1: ...Si18 525B Applied Models Super Multi Plus Cooling only Super Multi Plus Heat Pump D Series ...
Page 33: ...List of Functions Si18 525B 20 List of Functions ...
Page 71: ...Specifications Si18 525B 58 Specifications ...
Page 117: ...Refrigerant Flow for Each Operation Mode Si18 525B 104 Refrigerant Circuit ...
Page 171: ...Indoor Unit SkyAir Models Si18 525B 158 Function ...
Page 207: ...Test Operation and Field Setting for RA Indoor Unit Si18 525B 194 Test Operation ...
Page 336: ...Si18 525B Service Check Function Troubleshooting 323 ...
Page 469: ...Wiring Diagrams Si18 525B 456 Appendix ...
Page 475: ...Si18 525B vi Index ...