Installation and Maintenance Manual

Installation - Mechanical
56 RLC-SVX09H-EN
Condenser Water Piping (RTWD Units Only)
Condenser water inlet and outlet types, sizes and locations
are given in the Unit Dimensions andWeights. Condenser
pressure drops are shown inFigure 29, p. 51 thru
Figure 32, p. 54.
Condenser Piping Components
Condenser piping components and layout vary,
depending on location of connections and water source.
Condenser piping components generally function
identically to those in the evaporator piping system, as
described in "Evaporator Piping" on Page 40. In addition,
cooling tower systems should include a manual or
automatic bypass valve that can alter the water flow rate,
to maintain condensing pressure. Well water (or city
water) condensing systems should include a pressure
reducing valve and a water regulating valve.
Pressure reducing valve should be installed to reduce
water pressure entering the condenser. This is required
only if the water pressure exceeds 150 psig.This is
necessary to prevent damage to the disc and seat of the
water regulating valve that can be caused by excessive
pressure drop through the valve and also due to the design
of the condenser. Condenser waterside is rated at 150 psi.
Water Regulating Valve (RTWD Only)
The Condenser Head Pressure Control Option provides for
a 0-10V (maximum range - a smaller range is adjustable)
output interface to the customer’s condenser water flow
device. Refer to RLC-PRB021-EN for further details
regarding condenser water temperature control.
The following guidelines must be met in order to ensure
adequate oil circulation throughout the system.
• The RTWD requires a minimum pressure differential of
25 psid (172.1 kPA) at all load conditions in order to
ensure adequate oil circulation.
• The entering condenser water temperature must be
above 55°F (12.8°C), or between 45°F (7.2°C) and 55°F
(12.8°C) with a 1°F (0.6°C) temperature rise per minute
up to 55°F (12.8°C).
• The leaving condenser water temperature must be
17°F (9.4°C) degrees higher than leaving evaporator
water temperature within 2 minutes of startup. A 25°F
(13.9°C) temperature differential must be maintained
thereafter. (This differential requirement is lessened by
0.25°F [0.14°C] for every 1°F [0.6°C] that the leaving
condenser water temperature is above 55°F [12.8°C].)
If the above guidelines cannot be met, then some form of
condenser water temperature control must be used.
Note: Plugged tees are installed to provide access for
chemical cleaning of the condenser tubes.
Condenser piping must be in accordance with all
applicable local and national codes.
Condenser Drains
The condenser shells can be drained by removing the
drain plugs from the bottom of the condenser heads. Also,
remove the vent plugs at the top of the condenser heads
to facilitate complete drainage.
When the unit is shipped, the drain plugs are removed
from the condenser and placed in a plastic bag in the
control panel, along with the evaporator drain plug.The
condenser drains may be connected to suitable drains to
permit drainage during unit servicing. If they are not, the
drain plugs must be installed.
WaterTreatment
Using untreated or improperly treated water in these units
may result in inefficient operation and possible tube
damage. Consult a qualified water treatment specialist to
determine whether treatment is needed.The following
disclamatory label is provided on each RTWD unit:
Water Pressure Gauges
Install field-supplied pressure gauges (with manifolds,
when practical) on the RTWD units. Locate pressure
gauges or taps in a straight run of pipe; avoid placement
near elbows, etc. Install gauges at the same elevation.
To read manifolded pressure gauges, open one valve and
close the other (depending upon the reading desired).This
eliminates errors resulting from differently calibrated
gauges installed at unmatched elevations.
Water Pressure Relief Valves
Install a water pressure relief valve in the condenser and
evaporator leaving chilled water piping. Water vessels
with close coupled shutoff valves have a high potential for
hydrostatic pressure buildup on a water temperature
increase. Refer to applicable codes for relief valve
installation guidelines.
NOTICE:
Equipment Damage!
To prevent damage to the condenser or regulating
valve, the condenser water pressure should not exceed
150 psig.
NOTICE:
Proper WaterTreatment!
The use of untreated or improperly treated water could
result in scaling, erosion, corrosion, algae or slime. It is
recommended that the services of a qualified water
treatment specialist be engaged to determine what
water treatment, if any, is required. Trane assumes no
responsibility for equipment failures which result from
untreated or improperly treated water, or saline or
brackish water.