Service manual

Basic Control SiUS28-902_a
17 Function
2. Basic Control
2.1 Normal Operation
 Cooling Operation
 Heating Operation
∗ Heating operation is not functional at an outdoor air temperature of 86°FDB or more.
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 Cooling fan control ⎯
Four-way valve OFF ⎯
Main electronic expansion valve (EV1) 1400 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 —
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
> 454 psi.
Four-way valve ON ⎯
Main electronic expansion valve (EV1) PI control ⎯
Subcooling electronic expansion valve
(EV2)
0 pls ⎯
Hot gas bypass valve (SVP) OFF
This valve turns on with low pressure protection
control.
Receiver gas discharging valve (SVG) OFF —