SPX Cooling Technologies MARLEY AV 98-1514E - Manual (Page 14)

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When biocidal treatment has been maintained at a satisfactory level for
at least six hours, the fan may be turned on and the system returned
to service. Resume the standard water treatment program, including
biocidal treatment.
Tower Operation
general:
The cold water temperature obtained from an operating cooling tower will
vary with the following influences:
1. Heat load: With the fan in full operation, if the heat load increases,
the cold water temperature will rise. If the heat load reduces, the cold
water temperature will reduce.
Note that the number of degrees (“range”) through which the tower
cools the water is established by the system heat load and the amount
of water being circulated, in accordance with the following formula:
Operation
Range – °F =
Heat Load (Btu/hr)
GPM x 500
or — in SI units
Range – °C =
Heat Load (kilowatts)
Liters/sec x 4.187
The cooling tower establishes only the cold water temperature attain-
able under any operating circumstance.
2. air wet-bulb temperature: Cold water temperature will also vary with
the wet-bulb temperature of the air entering the louvered faces of
the tower. Reduced wet-bulb temperatures will result in colder water
temperatures. However, the cold water temperature will not vary to the
same extent as the wet-bulb. For example, a 20°F (11 °C) reduction
in wet-bulb may result in only a 15°F (8°C) reduction in cold water
temperature.
3. Water flow rate: Increasing the water flow rate (GPM or L/s) will cause
a slight elevation in cold water temperature, while reducing the water
flow rate will cause the cold water temperature to decrease slightly.
However, at a given heat load (see formula above), water flow reduc-
tions also cause an increase in the incoming hot water temperature.
Use care to prevent the hot water from exceeding 125°F, (52°C) in