| Application and Design Information (cont.)
Allow approximately 3 inches of
space for the discharge connection. The amount of flexible material used should be
about twice the width of the gap to adequately absorb
any vibration. Be sure the canvas is kept loose after installation.
Piping Connections
In general, rubber isolator connectors are recommended for condenser piping
to prevent vibration transmission to the building
plumbing. The Trane unit is internally isolated and may not require this
additional expense. However, do not forget to
design in proper system vibration isolation to prevent vibration transmission from the building plumbing to the unit. Also be
sure the drain line is properly isolated.
Electrical Connections
Flexible conduit improves the ease of installation but is not required because
the Trane unit is internally isolated. This also
protects the unit from vibration originating outside
the unit.
Condenser Water Piping And Component Recommendations Piping Location And Arrangement
Provide at least 24 inches of clearance between the piping and the unit for
service. Place the risers away from the side of the
unit if possible. Be sure to allow sufficient space for valves and unions between the piping and the self-contained unit.
Condenser piping should be laid out in reverse returns to help balance the system. This is accomplished by equalizing the
length of supply and return pipes.
Multi-story buildings may use a direct return system with balancing valves at
each floor. All heat exchangers and most tower piping
should be installed below the sump operating water level in order to prevent
overflow at unit and/or system shutdown.
Recommended Pump Location
Pump location is preferred downstream of the cooling tower and upstream
of the self-contained unit. This provides smoother and
more stable unit operation.
When the tower and pump are both roof mounted, be sure to provide the necessary
net positive suction head to prevent cavitation. The
tower can be raised or the pump can be submerged in a sump to provide the positive suction.
A standby pump is recommended to avoid a complete system shutdown in the event
of an on-line pump failure.
Several partial capacity pumps or variable speed pumps may be used. Review the
economics of these alternate pumping options.
Strainers And Water Treatment
Water strainers located at the inlet to each unit are an absolute must. Be sure to specify a water basket strainer to
avoid incorrect application of a steam strainer.
Untreated or poorly treated water may result in equipment damage. Consult a
water treatment specialist for treatment
recommendations.
Isolation Valves
Install isolation valves at each unit before the strainer and after the condenser.
This allows periodic servicing of the unit or strainer
with the remainder of the units still in operation.
Pressure Gauges
Install pressure gauges on the inlet and outlet of the self-contained unit. A 3-inch face diameter gauge is recommended
with the operating point close to the midpoint reading
of the gauge.
Thermometers
Thermometers are recommended on the inlet and outlet of the condenser water
lines to each unit. The recommended temperature range
for the thermometer is 40 to 140 degrees Fahrenheit. A 2-degree temperature
increment is recommended.
Drains
The unit condensate drain must have a trap to offset the pressure differential
that exists when the fan is operating. The Trane
unit provides a factory installed internally trapped
drain.
The low point of the floor of the mechanical equipment should have a
drain for collection of water from cleaning operations.
Condensing Pressure Control Valve
In many cases a condensing pressure control valve is required for cold condensing water applications. THE CONDENSING
PRESSURE CONTROL VALVE IS NOT REQUIRED WHEN USING A WATERSIDE ECONOMIZER FROM
TRANE.
If you do not have a Trane waterside economizer, when using city or cold tower water (i.e. water below 55 F), install a
condensing pressure control valve. Other operating
conditions such as low water pressure may also require a valve. |
