Trane IntelliPak SAHL Series Installation, Operation And Maintenance Manual page 189

Evaporative Condenser Coil
Sump Water Management
Water Supply
Overall performance of any water- cooled device can be affected by suspended particulates,
mineral concentration, trash and debris resulting in clogging and heat transfer loss. The unit is
designed to greatly minimize problems with these impurities, however, float valves and solenoid
valves are used to control the incoming water.
If the incoming water contains contaminants, sand or other objects, it is best to insert an incoming
line strainer having a mesh of 80 to 100. The inlet line should be flushed prior to connection to the
unit, whether or not there is a strainer.
There is an air gap between the water inlet float valve and sump water level to prevent back flow;
however, if local code dictates, a backflow prevention valve may be required (field-provided and
installed by others).
Water Drain
Local Site Discharge: Rooftop or simple storm sewer discharge is generally acceptable. Do not
routinely direct the sump discharge onto an area that will be adversely affected. For example,
continued sump discharge into a flower bed where the input water contains CaCO3 (lime) will
eventually decrease the pH of the soil.
Sewer Discharge: The quantities of mineral and debris flushed are actually very small and do not
cause problems when diluted in normal sewer flow. However, local, state or federal standards and
restrictions must be followed in any given locality.
Traditional Bleed Method
ASHRAE recommendation for continuous bleed rates:
With good, quality makeup water, the bleed rates (0.8 - 2 GPH/ton) may be as low as one-half the
evaporation rate (1.6 -2 GPH), and the total water consumption would range from 2.4 GPH/ton for
air conditioning to 3 GPH/ton for refrigeration (Chapter 36.17 of ASHRAE's "Systems and
Equipment Handbook")
Operation and Care
The sump should be inspected at least every 6 months for possible build up of scale pieces that
has been shed from the coils. The sump flush frequency or bleed rate should be increased if large
amounts of scale are present.
If the water has a "milky or cloudy" appearance, then minerals are concentrating in the sump and
the number of flushes should be increased.
If the water remains clear between flushes, then the number of flushes can be decreased. Through
field trials, the optimum flush frequency can be determined. Please note that in some areas, water
quality can vary during different times of the year. The sump water clarity should be checked
periodically.
The evaporative condenser has several design features to reduce the possibility of biological
growth in the sump. These features include:
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Important: Do not use chlorine tablets directly on stainless steel surface as it can adversely
RT-SVX36G-EN
Air inlets constructed to eliminate direct sunlight in the sump
The sump flush sequence replenishes the sump with fresh water 1 to 12 times per day
depending on the flush setting
The copper tubing in the coils is a natural biocide
affect its corrosion resistance.
Maintenance
189