Daikin IOM 1322-1, Installation, Operation And Maintenance Manual

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Application Considerations
www.DaikinApplied.com 11 IOM 1322-1 • WATER-COOLED SCROLL COMPRESSOR
Condensers are drained of water in the factory and are shipped
with the condenser drain plugs in the heads removed and
stored in a bag in the control panel. Be sure to replace plugs
prior to filling the vessel with fluid.
Water-cooled condensers can be piped for use with cooling
towers, well water, or heat recovery applications. Cooling
tower applications must be made with consideration of freeze
protection and scaling problems. Contact the cooling tower
manufacturer for equipment characteristics and limitations
for the specific application. Head pressure control must
be provided if the entering condenser water can fall below
60°F. The WGZ condenser has two refrigerant circuits with a
common condenser water circuit. This arrangement makes
head pressure control with discharge pressure actuated control
valves difficult.
If the tower water temperature cannot be maintained at a
60°F minimum, or when pond, lake, or well water that can fall
below 60°F (15°C) is used as the condensing medium, special
discharge pressure control must be used. A water recirculating
system with recirculating pump as shown in Figure 5:
Recirculating Discharge Water System is recommended. This
system also has the advantage of maintaining tube velocity to
help prevent tube fouling. The pump must cycle with the chiller.
Figure 5: Recirculating Discharge Water System
Components
Figure 6: Compressor Locations
Packaged Unit Refrigerant
Piping
WGZ 030DW to 130DW have two refrigerant circuits, two
tandem scroll compressors (total of four), a single two-circuited
brazed plate evaporator, a single two-circuited water-cooled
condenser, interconnecting refrigerant piping and a control
panel with associated sensors and transducers. Models WGZ
150DW to 200DW have two trio-compressors (total of 6) and
a shell-and-tube evaporator. Packaged units are provided with
complete refrigerant piping and full operating refrigerant charge
at the factory.
Figure 7: Schematic Piping Diagram (One of Two Circuits for Brazed Plate Evaporators)