Cooling Tower Cleaning - SPX Marley NC Series Installation Operation & Maintenance

maintenance

Cooling Tower Cleaning:

Any evaporative-type cooling tower must be thoroughly cleaned on
Warning
a regular basis to minimize the growth of bacteria, including Legio-
nella Pneumophila, to avoid the risk of sickness or death. Service
personnel must wear proper personal protective equipment during
decontamination. Do NOT attempt any service unless the fan motor
is locked out.
Operators of evaporative cooling equipment, such as water cooling towers,
should follow maintenance programs which will reduce to an absolute minimum
the opportunity for bacteriological contamination. Public Health Service officials
have recommended that "good housekeeping" procedures be followed, such
as: regular inspections for concentrations of dirt, scale, and algae; periodic
flushing and cleaning; and the following of a complete water treatment program
including biocidal treatment.
The visual inspection should take place at least once a week during the operat-
ing season. The periodic flushing and cleaning should be done before and after
each cooling season, but in any event at least twice a year. The louvers, drift
eliminators, and easily accessible fill surfaces should be flushed by use of a
moderate-pressure water nozzle, being careful not to cause physical damage.
A reliable water treatment program should be installed and maintained. Filtra-
tion devices may be employed to reduce the suspended solids concentrations,
thus increasing the effectiveness of the water treatment program. See Tower
Startup section of this manual.
Blowdown:
A cooling tower cools water by continuously causing a portion of it to evaporate.
Although the water lost by evaporation is replenished by the makeup system, it
exits the tower as pure water—leaving behind its burden of dissolved solids to
concentrate in the remaining water. Given no means of control, this increasing
concentration of contaminants can reach a very high level.
In order to achieve water quality which is acceptable to the cooling tower (as
well as the remainder of your circulating water system), the selected water
treatment company must work from a relatively constant level of concentra-
tions. This stabilization of contaminant concentrations is usually accomplished
by blowdown, which is the constant discharge of a portion of the circulating
water to waste. As a rule, acceptable levels on which to base a treatment
schedule will be in the range of 2-4 concentrations. The following table shows
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