Danfoss AK2-SC 255, Reference Manual, Page: 44 / 206

RS.8D.M1.22 AK2-SC 255 Reference Manual 43
255.
Evaporative: There are evaporative condensers that
are controlled by the SC 255. The remainder of this
section (this screen and the next four) pertain to this
selection.
Air Cooled: The SC 255 is controlling air-cooled
condensers. The configuration of air-cooled condens-
ers is covered in the preceding section of this manual.
Number of pumps (0 to 2) The number of coolant pumps.
Daily rotation (List box: Yes, No) Whether or not pumps will rotate.
Monitor stages (List box:)
Individual: Fans will be monitored individually with a
digital input (on-off input) created for each fan.
Paired: Fans will be monitored in pairs with a digital
input created for each pair.
None: Fans will not be monitored.
Control sensor (List box)
Pressure: A pressure sensor will be used to control
the condenser fans. An analog input (sensor input) will
be created for the sensor.
Dropleg Temp: A temperature sensor on the drop leg
will be used to control the condenser fans. An analog
input (sensor input) will be created for the sensor.
Monitor dropleg temp (List box: Yes, No) (Appears if control is by pressure)
Whether the drop leg temperature will be monitored. A
Yes answer here will create an analog input (sensor
input) for the drop leg temperature sensor.
Control method (List box:)
Target: The condenser fans will be controlled to
maintain a target pressure or dropleg temperature,
depending on which strategy is selected by the answer
to the Control sensor question above.
Cutin Cutout: The condenser will be controlled by
cut-in and cut-out based on target pressure or satu-
rated condensing temperature, depending on which
strategy is selected by the answer to the Control
sensor question above. If Cutin Cutout is selected,
the next page will provide for selection of cut-in and
cut-out setpoints. The page is not shown here, but is
straightforward.
Target control type [Please read about all of the possible answers:]
(List box:)
Ramp together: Where there is variable speed fan
motor control, all fans will be brought on in stages at
minimum speed, then ramped up in speed as a group.
Ramp stages: Where there is variable speed fan
motor control, each stage will be brought on and
ramped up to maximum speed. When additional
capacity is required, fans will be reduced to minimum
speed and an additional stage brought on, then all will
be ramped up together, and so on.