Connection Sizes, Fluid Coolers (Dry Coolers); Auxiliary Chilled Water/Energy Saver Coil; Auxiliary Chilled Water/Energy Saver Coil Piping - Data Aire DAPA-2.5 Installation, Operation & Maintenance Manual

Connection Sizes, Fluid Coolers (Dry Coolers)

The information regarding Fluid Cooler (or often referred to as a "dry cooler") connection sizes can be
found in the individual Fluid Cooler User Manuals which should be referred to for more complete details.

Auxiliary Chilled Water/Energy Saver Coil

In colder climates, the evaporator will often be equipped with an additional free cooling coil to take
advantage of the colder ambient temperatures. When incoming fluid falls below the setpoint of a water
sensing thermostat in the evaporator, typically about 50°F (10C), the energy saver cooling becomes
available.
Systems with an Energy Saver coil (identified with a - E suffix to the model number) should have at
least one fluid sensing thermostat on the fluid cooler set lower to take advantage of colder ambient
temperatures. The desired fluid temperature for energy saver cooling is 45°F (7.2C). Field adjustment
of fluid sensing thermostats is not unusual.
It is desirable to use the energy saver mode as much as possible. However, fluid temperature that is
too cold can cause excessive dehumidification and coil sweating. Fluid temperature that is too high can
also cause the indoor space temperature to rise. This could cause the evaporator's microprocessor
control to lock out the energy saver mode for one (1) hour while it reverts to compressor (mechanical)
cooling. Adjust the setpoints of the thermostats to allow the maximum free cooling time. Over cooling
or under cooling the fluid should be avoided.
The water sensing thermostats on the outdoor fluid cooler section have adjustable set points which are
typically staggered to maintain water temperature in the 85° to 105°F (29.4° to 40.6°C) range. This is
generally the desired range for glycol cooled systems.
A surge tank is standard on all fluid coolers. This is enough on most applications; however, an
expansion tank should be installed at the highest point in the system and the point of least pressure.

Auxiliary Chilled Water/Energy Saver Coil Piping

Units with Auxiliary Chilled Water-cooling coil (identified with a - C suffix to the model number) require
a separate source of chilled water. These chilled water connection sizes will be equal to the condenser
water connection sizes shown in the Fluid Cooler Operation, Installation and Maintenance manual.
Units with an Energy Saver cooling coil have shared piping with the condenser supply and return
therefore do not require a separate water source.
All chilled water pipes have a cap installed on the end of the pipe for factory pressure testing of the
system. These caps need to be removed before installing the water piping to the unit. Use a tube cutter
for smaller pipes and reciprocating saw with a metal cutting blade for larger pipes or if there is a
clearance problem. All connections need to be cleaned before connections are brazed together.
NOTE: Every application will have a different ambient temperature and indoor
heat load/air distribution profile. Therefore it is not possible to dictate the exact
water sensing thermostat setpoints. Field adjustments are typical to allow "fine
tuning" to specific conditions.
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