Specifications

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Noise factors should also be considered when locating an air cooled heat exchanger. Proximity
to windows, walls and surrounding structures can cause objections by the occupants. An acoustical
expert should be consulted when noise is of a particular concern.
Air cooled heat exchangers should be placed at a level that is higher than the indoor evaporator.
The mounting of the remote heat exchanger more than 10 feet below the evaporator is not
recommended. Excessive liquid line pressure drop can cause poor evaporator performance.
Piping must be supported within 18 inches of the inlet and outlet connections. The inlet connection
is located on the top header on all remote heat exchangers and the outlet connection is located on
the bottom header of all units.
4.4 Electrical Service
Refer to Sections 3.1 to 3.5 for information regarding line voltage and control voltage wiring
details.
4.5 Air Cooled Condensers - Model DARC
4.5.1 Fan Speed Control
The standard Data Aire condenser (DARC) utilizes a fan speed controller. On single fan
condensers this is the only means of control.
Multiple fan condensers are provided with fan speed control on the fi rst motor (nearest the header).
The fan speed control is pre-programmed and there is no need to adjust the unit in the fi eld. The
header fan will cycle with the head pressure of the unit.
Units shipped with R-407C the starting pressure is 220 PSIG and the fan will be at full speed at
285 PSIG. Units shipped with R-410A the starting pressure is 320 PSIG and the fan will be at full
speed at 400 PSIG. The second fan operates in conjunction with the speed controlled fan. The fan
speed control powers ON the auxiliary and shifts the speed controlled fan to a new start pressure.
4.5.2 Ambient Thermostats
Additional motors (subsequent to the fan speed control operated motors) multiple fan heat
exchangers are cycled by ambient sensing thermostats. These thermostats have a capillary tube
with remote sensing bulb. They function best with the sensing bulbs mounted below the coil, away
from exposure to direct sunlight with the bulb in the vertical position. An instruction set comes as
part of a mounting kit that includes a sheet metal bracket, mounting clamps and TEK screws. This
includes directions for fi eld mounting and adjustment. Desired head pressure should be maintained
at approximately 340-400 PSIG for R-410A and 230-270 PSIG for R-407C.
Typical settings for the ambient thermostats are as follows:
Number of Fans Header Fan Fan 2 Fan 3 Fan 4 Fan 5
2 FSC Pressure Control
3 FSC Pressure Control 75°
4 FSC Pressure Control 85° 75°
5 FSC Pressure Control 85° 75° 65°