Figure 21: Schematic of a typical piping arrangement
Condenser water circuit
For proper operation of the unit, condenser refrigerant pressure must be maintained above
evaporator pressure. If operating conditions will fulfill 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 efficiently
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, refer to the Unit Operation Manual (Form 160.79-OM1) condenser water temperature must
be maintained equal to or slightly higher than the required minimum. See Figure 21 for typical
water piping arrangement.
Stop valves
Stop valves may be provided (by others) in the evaporator and condenser water piping adjacent
to the unit to facilitate maintenance. Thermometer wells and pressure taps must be provided (by
others) in the piping as close to the unit as possible to facilitate operating check.
Flow switches
Thermal type water flow switches are factory mounted in the chilled and condensed water nozzles
and are factory wired to the OptiView control panel. These solid-state flow sensors have a small
internal heating element and use the cooling effect of the flowing fluid to sense when an adequate
flow rate has been established.
Drain and vent valves
Drain and vent valves (by others) should be installed in the connections provided in the evaporator
and condenser liquid heads. These connections may be piped to drain if desired.
Checking piping circuits and venting air
After the water piping is completed, but before any water box insulation is applied. Tighten and
torque to maintain between 30 ft-lb and 60 ft-lb (41 N·m and 81 N·m) the nuts on the liquid head
flanges. Gasket shrinkage and handling during transit cause nuts to loosen. If water pressure
is applied before tightening is done, the gaskets may be damaged and have to be replaced. Fill
39Centrifugal Liquid Chillers
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