Dunham-Bush WCFX-E Series Manual Download Page 34

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EQUIPMENT

Standard Equipment And Factory
Installed Options

Dunham-Bush Water Cooled Screw Flooded Chillers, like
many other Dunham-Bush products, distinguish
themselves by offering as standard many features that
other manufacturers provide only as costly options.

Some of the Standard Features of these chillers which
provide for efficiency and reliability are:

Addition of service valve in suction and vapor injection
lines on each compressor allow replacement of one
compressor while others are running and also allow
refrigerant storage in the evaporator via a service
compressor.

Unit mounted and wired reduced inrush starting
system.

Factory mounted and wired control power transformer.

Single point electrical power connection.

Undervoltage phase failure relay.

Controller monitoring of evaporator leaving water
temperature.

Controller monitoring of suction & discharge
pressures.

Controller monitoring of power supply volts.

Controller monitoring of single phase amps for each
compressor.

Controller monitoring of each compressor, number of
starts (cycles) and elapsed time for both a by hour
period or total time and cycles.

Units shipped completely factory tested, charged and
adjusted for ease of installation and minimal

field start-up adjustments.

Chilled water reset from control panel or external
building automation system.

High oil temp, low oil level, freeze, low suction
pressure, high discharge pressure, and solid state
overload protection are all featured.

Unit mounted circuit breaker for each compressor on
two and three compressor units.

Discharge check valves on multiple compressor units
allow refrigerant charge to be stored in the condenser
for service to compressor or evaporator.

Additional Features offered by Dunham-Bush as Factory
Installed Options include:

Insulation of all low temperature surfaces.

Hot gas bypass for very low load situations.

Controller monitoring of return chilled water and
entering and leaving condenser water in addition to
the standard leaving chilled water temperature.

Personal computer with communication software
installed to enable the remote monitoring of all
functions and inputs to the controller.

Dual bundle heat reclaim condensers are available for
special applications.

Control of up to five packages via a master slave
arrangement requiring only two shielded cables
between units. Up to ten packages can be controlled
via an Equipment Management Center.

Unit mounted disconnect switch 400 to 575 volts
applications.

Flanged semi-hermetic compressor.

Discharge service valve for MSC 226 series

compressor.

GUIDE SPECIFICATIONS

1. The contractor shall in accordance with the plans,

furnish and install _____________ Dunham-Bush
_______________ packaged liquid chiller(s). The
unit(s) shall be completely factory packaged including
rotary screw compressor(s), evaporator, condenser,
and control panel. The packaged chiller shall be
factory assembled, charged and tested with a full
operating refrigerant and oil charge. The refrigerant
type shall be R134a.

2. Capacity of each chiller shall be not less than

_________________ refrigerant tons (kW output)
cooling at _____________ GPM (liters/min.) of water
from __________ °F(°C) to _________ °F(°C). Power
input requirements for the unit(s), incorporating all
appurtenances necessary for unit operation, including
but not limited to the control accessories and pumps,
if required, shall not exceed ___________kW input at
design conditions. The unit shall be able to unload to
_______% of cooling (refrigeration) capacity when
operating with leaving chilled water and entering
condenser water at design temperatures. The unit
shall be capable of continuous operation at this point,
with stable compressor operation, without the use of
hot gas bypass.

3. Heat transfer surfaces shall be selected to reflect the

incorporation of a fouling factor of .00025 hr.sq.ft.
°F/BTU (0.000044m².°C/W) for the water condenser
and 0.0001 for evaporator. Water pressure drop at
design conditions shall not exceed ___________ feet
of water through the condenser, and ____________
feet of water through the evaporator.

4. The packaged chiller shall be furnished with single-

stage direct connected positive displacement rotary
screw compressor(s) as required, driven by a 3500
RPM (2900 RPM-50Hz) motor. Each compressor shall
include integral oil separation system, oil sump and oil
filter. The oil differential pressure shall be controlled
during operation to maintain proper oil lubrication
throughout the lubrication system. An electric oil
heater shall be supplied with each compressor to
maintain oil temperature during shutdown period.
Each compressor shall have a suction check valve,
suction filter, (suction service valve) (and a discharge
check valve). Compressor capacity control shall be
obtained by an electrically initiated, hydraulically
actuated slide valve within each compressor. (Provide
isolation valves on all connections to compressor to
allow condenser to be used as a pump down
receiver).