CyberAiR DX Floor Mounted IOM Manual
1.8
Alternate Water Source Operation
An alternate water source (AWS) system utilizes an independent chilled water source to provide coolant to an
AWS cooling coil in the A/C unit. If AWS cooling is unable to handle the load, the separate DX refrigeration circuit
can be utilized to assist. Similar to FC operation, when return air temperature rises to the AWS cut-in
temperature set point, AWS cooling activates (the AWS control valve opens) provided the chilled water inlet
temperature is 55°F or cooler (adjustable).
If the return air temperature rises
to the compressor cut-in set point
or if the AWS control valve
reaches 100% open for the
compressor delay period (20
seconds,
adjustable), the compressor turns
on and operates in parallel with
AWS cooling. The compressor runs
until the cut-out set point
temperature is reached provided
the minimum run time expires.
AWS cooling will continue if the
return air temperature is above
the AWS cooling cut-in
temperature set point and the
chilled water inlet temperature is
55°F or cooler.
If the chilled water temperature
is above 55°F, AWS cooling
turns off (the control valve
closes). If the compressor cut-in
set point is reached, the
compressor turns on
and becomes the primary source
of cooling.
In the event of loss of water
flow during AWS operation,
the AWS control valve is
closed and
compressor operation is activated.
Figure 6- Alternate Water Source Diagram
1-11
