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The water-sensing thermostats have adjustable setpoints which are typically staggered to maintain
water temperature in a range of 85 to 105°F. This is generally the desired range for glycol cooled
systems.
A surge tank is standard with all DAFC fl uid coolers. This is suffi cient for most applications. How-
ever, an expansion tank should be installed at the at the highest point in the system and the point
of least pressure.
4.6.2 Energy Saver Cooling
In colder ambient climates units may be equipped with an additional free cooling coil. When incom-
ing fl uid temperature falls below the setpoint of a water-sensing thermostat in the evaporator (typi-
cally 50°F), Energy Saver or free cooling becomes available.
Systems with an Energy Saver coil should have at least one fl uid-sensing thermostat on the fl uid
cooler set lower to take advantage of the colder ambient temperatures. The desired fl uid tempera-
ture for Energy Saver cooling is 45°F. Field adjustment of fl uid sensing thermostats is not unusual.
It is desirable to use the Energy Saver mode as much as possible to maximize the free cooling
feature. However, fl uid temperature that is too cold can cause excessive dehumidifi cation and coil
sweating. Fluid temperature that is too high can cause the indoor space temperature to rise. This
could cause the evaporator’s microprocessor control to lock out the Energy Saver mode for one
hour while it reverts back to compressor (mechanical) cooling. Adjust setpoints of the thermostats
to allow the maximum free cooling time. Over cooling or under cooling the fl uid should be avoided.
WARNING: Every application will have a different ambient temperature and indoor heat
load/air distribution profi le. It is not possible to dictate the exact water-sensing thermo-
stat setpoints. Field adjustments are typical to allow fi ne tuning to specifi c conditions.
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