035-19569-101 (0109)
4-5
GB
4.9.1 Chilled Water Circuit
Foreign objects which could lodge in, or block fl ow
through the evaporator and condenser tubes must be
kept out of the water circuit. All water piping must be
cleaned or fl ushed before being connected to the chiller
pumps, or other equipment.
Permanent strainers (supplied by others) are required
in both the evaporator and condenser water circuits to
protect the chiller as well as the pumps, tower spray
nozzles, chilled water coils and controls, etc. The
strainer should be installed in the entering chilled water
line, directly upstream of the chiller.
Water piping circuits should be arranged so that the
pumps discharge through the chiller, and should be
controlled as necessary to maintain essentially constant
chilled and condenser water fl ows through the unit at all
load conditions.
If pumps discharge through the chiller, the strainer may
be located upstream from pumps to protect both pump
and chiller. (Piping between strainer, pump and chiller
must be very carefully cleaned before start-up.) If pumps
are remotely installed from chiller, strainers should be
located directly upstream of the chiller.
4.9.2 Condenser Water Circuit
For proper operation of the unit, condenser refrigerant
pressure must be maintained above evaporator pressure.
If operating conditions will fulfi ll this requirement, no
attempt should be made to control condenser water
temperature by means of automatic valves, cycling of
the cooling tower fan or other means, since chillers are
designed to function satisfactorily and effi ciently when
condenser water is allowed to seek its own temperature
level at reduced loads and off-peak seasons of the
year. However, if entering condenser water temperature
can go below the required minimum, condenser water
temperature must be maintained equal to or slightly
higher than the required minimum. Refer to Figure 4.3
for a typical water piping schematic.
Figure 4.3 Schematic of a Typical Piping Arrangement
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