SPX Cooling Technologies CoolingTower Marley MCW - Manual (Page 12)

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Some trial and error adjustment of the float valve may be required to
balance the makeup water with tower operation. Ideally, the float valve
setting will be such that no water is wasted through the overflow at
pump shutdown. However, the water level after pump start-up
must
be deep enough to assure positive pump suction.
5. Continue pump operation for about 15 minutes, after which it is rec-
ommended that the water system be drained, flushed, and refilled.
6. While operating the condensing water pump(s) and prior to operat-
ing the cooling tower fan, execute one of the two alternative biocidal
treatment programs described in the following:
• Resume treatment with the biocide which had been used prior
to shutdown. Utilize the services of the water treatment supplier.
Maintain the maximum recommended biocide residual (for the
specific biocide) for a sufficient period of time (residual and time
will vary with the biocide) to bring the system under good biological
control
or
• Treat the system with sodium hypochlorite to a level of 4 to 5 mg/L
free chlorine residual at a pH of 7.0 to 7.6. The chlorine residual
must be held at 4 to 5 mg/L for six hours, measurable with standard
commercial water test kits.
If the cooling tower has been in operation and then shut down for a
duration of time and not drained, perform one of the two previous
biocidal treatment programs directly to the cooling water storage
vessel (cooling tower sump, drain down tank, etc.) without circulat-
ing stagnant water over the cooling tower fill or operating the cooling
tower fan.
After biocidal pretreatment has been successfully completed, cooling
water may be circulated over the tower fill with the fan off.
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.
Installation