Description of Functions and Operation
SiENBE28-901
52
Air Cooled Refrigeration Condensing Unit
(4) Fan control
(4)-1. Outdoor fan control
The outdoor fan will be controlled using the high pressure as the controlled variable, as
shown in the flow below.
(4)-2. Fan control before startup
The fan revolution will be set based on the outdoor temperature. This is intended to
prevent the pressure from rising too rapidly and ensure the proper differential pressure.
(4)-3. Outdoor fan residual operation
Reduces the high pressure to some degree when the thermostat is turned off. This will
minimize the amount of sluggish refrigerant that is trapped due to high pressure when the
system is stopped.
The fan will operate continuously for either 30 seconds after the compressors are turned
off, or as long as the high pressure (HP) stays below 1.18 MPa.
(4)-4. Fan upper limit control based on the outdoor temperature
The fan upper speed will be limited based on the outdoor temperature. This will help
reduce the operating sound.
Outdoor fan
Lpm: Pressure equivalent to the target evaporation temperature
HP: High pressure
or
Fan control
Fan speed-up
control
Fan speed-down
control
Every 20 to
60 seconds
Every 60
seconds
Increases the
speed by 1 tap.
Reduces the
speed by 1 tap.
High pressure
fan control
INV fin temperature
control
• Lpm < 0.59 MPa
• HP > 1.86 MPa
<For 5, 6, 15, and 20AY1 models>
&
&
• Lpm
≥
0.59 MPa
• HP > Lpm + 1.27 MPa
<For 8, 10, and 12AY1 models>
• HP
≥
Lpm + 1.47 MPa
<For 5, 6, 15, and 20AY1 models>
&
• HP < Lpm + 0.69 MPa
• HP < 1.27 MPa
<For 8, 10, and 12AY1 models>
• HP < Lpm + 0.88 MPa
TcL: Saturation temperature equivalent to high pressure
Ta:
Outdoor temperature
• HP
≥
2.74 MPa ······ Max. fan tap
&
• HP
≥
2.45 MPa
• TcL > Ta + 18°C ······· Increases the speed by 2 taps.
&
• HP
≥
2.45 MPa
• TcL
≤
Ta + 18°C ······ Increases the speed by 1 tap.
&
• HP
≥
2.45 MPa
• While the outdoor fan is not in operation ······ Increases the speed by
1 tap.
(This assumes that the low pressure outdoor fan is being controlled.)
Inverter fin temperature > 79°C ······ Increases the speed by 1 tap.
Outdoor temperature
Ta<3°C
3°C
≤
Ta
<9°C
9°C
≤
Ta
<15°C
15°C
≤
Ta
<21°C
21°C
≤
Ta
<28°C
Ta
≥
28°C
LRM(L)EQ5AY1,6AY1
0
2
3
4
5
6
LRM(L)EQ8AY1,10AY1,12AY1
0
2
3
4
5
6
LRM(L)EQ15AY, 20AY1
0
2
3
4
5
6
Fan tap
9 tap
6 or 7 tap
5 or 6 tap
26°C
28°C
31°C
33°C
Amb. temp. (°C)
