Minimum Water Volume For A Process Application; Unit Piping - Trane Cold Generator CG-SVX044F-EN Installation, Operation And Maintenance Manual

Installation Mechanical
systems with a rapidly changing load profile the volume should
be increased.
If the installed system volume does not meet the above
recommendations, the following items should be given careful
consideration to increase the volume of water in the system
and, therefore, reduce the rate of change of the return water
temperature.
• A volume buffer tank located in the return water piping.
• Larger system supply and return header piping (which also
reduces system pressure drop and pump energy use).
Minimum Water Volume for a
Process Application
If a chiller is attached to an on/off load such as a process load,
it may be difficult for the controller to respond quickly enough
to the very rapid change in return solution temperature if the
system has only the minimum water volume recommended.
Such systems may cause chiller low temperature safety trips
or in the extreme case evaporator freezing. In this case, it may
be necessary to add or increase the size of the mixing tank in
the return line.

Unit Piping

See "Piping System Flushing Procedure," p. 55
on piping system flushing procedure, and water treatment
requirements.
Exchanger Water Pressures
NOTICE
Vessel Damage!
To prevent pressure vessel damage, do not exceed unit
nameplate water-side pressures.
If field installed gauges are used, provide shutoff valves in the
line(s) to the gauge(s) to isolate the gauges when not in use.
Flow Sensing Devices
NOTICE
Unexpected Chiller Start!
Failure to follow instructions could cause the chiller to
start unexpectedly which could result in equipment or
property damage. An external source (EMS, time clock
or any other means) should not be allowed to bring on a
pump that would trigger the flow switch to start the
chiller. The flow switch is meant to act as a safety
switch and not a start/stop mechanism.
Chilled water flow switch, or other factory approved flow
proving device is mandatory; field installation by contractor is
required. Flow switch is to be installed and maintained per
manufacturer's recommendations and interconnected to the
control panel as described on the wiring diagram. To provide
24
additional chiller protection, install and wire the flow switch in
series with chilled water pump interlock for the chilled water
circuits. See
Specific connection and schematic wiring diagrams ship with
the unit inside the control box and in this IOM notebook.
Water Piping Recommendations
All water piping must be cleaned and flushed according to
"Piping System Flushing Procedure," p. 55
any water through unit.
Make sure water piping connections to the evaporator and
condenser are isolated, and confirm that all piping to unit is
supported independently to prevent any load being transferred
to the unit. Use unions, flanges or grooved lock type fittings to
facilitate service procedures. Use a pipe sealant such as
Teflon
®
eliminators to prevent transmitting vibrations through the water
lines. Construct and install piping in accordance with all local,
state and national codes.
Supply and insulate the chilled water piping as required, to
prevent sweating and minimize heat gain under normal
operating conditions. Chilled water piping must rise above the
chiller to ensure the evaporator is full of water and void of air at
all times. Install thermometers in the lines to monitor
evaporator entering and leaving water temperatures.
CICD chillers have manual balancing ball-valves in the
for information
entering water lines. They may be used to establish a balanced
water flow. Both the entering and leaving water lines have
valves that can be used to shutoff/isolate the evaporator and
condenser for service.
Equipment Damage!
To prevent equipment damage, you MUST follow
instructions below:
• Bypass unit when using a flushing agent.
• Chilled water piping must rise above the chiller to
ensure the evaporator is full of water and void of air
at all times.
• Do not over tighten connections.
Water Flow Rates
Establish balanced water flow through both the evaporator and
condenser. Flow rates should fall between the minimum and
maximum values given in General Data
rates above or below these values can cause equipment
damage or improper unit operation. The evaporator and
condenser water pressure drop can be read manually using
the factory-installed condenser inlet and outlet pressure gauge
service ports. Readings should approximate those shown by
the pressure drop charts for the individual chillers
p. 25 and
Note: Pressure drop is an approximation and is to be used as
"Required Chilled Water Flow Switch," p.
tape on all threaded water connections. Use vibration
NOTICE
Figure 15, p. 26).
a tool to estimate flow rate and as an aid to waterside
system piping design. If an accurate measurement of
32.
prior to circulating
Table 1, p. 7. Flow
(Figure 13,
CG-SVX044F-EN