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7. 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:
• Resumetreatmentwiththebiocidewhichhadbeenusedprior
to shutdown. Utilize the services of the water treatment supplier.
Maintain the maximum recommended biocide residual (for the
specicbiocide)forasufcientperiodoftime(residualandtime
will vary with the biocide) to bring the system under good biological
control
or
• Treatthesystemwithsodiumhypochloritetoalevelof4to5mg/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-
ingstagnantwateroverthecoolingtowerlloroperatingthecooling
tower fan.
After biocidal pretreatment has been successfully completed, cooling
watermaybecirculatedoverthetowerllwiththefanoff.
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