MTS Water Quality Guide - Manual (Page 9)

Heat Exchanger Care and Water Quality Guide Heat Exchanger Care 9
Water Chemistry
Cooling towers located in an industrialized area should be a closed-loop design
to provide protection against airborne contaminants.
Different types of contaminants in the cooling water supply may react in
combination to create corrosion rates a hundred times higher than would be seen
by either contaminant acting alone. Cooling towers, unless regularly treated and
controlled, are the systems that have had the most problems with corroded heat
exchangers.
Local industrial water treatment specialists can provide information on your
water conditions and solutions to contaminant problems.
Compounds found in water Allowable quantity (parts per million)
Ammonia none
Bacteria must be bacteriologically safe
Calcium <800 ppm
Chlorides <5 ppm
Dissolved solids >50 but <500 ppm; limit to 150 ppm if
abrasive solids present
Iron 3 ppm
Nitrates <10 ppm
Nitrogen compounds none
Oxidizing salts or acids none
pH level 6–8.5 recommended
Silica as SiO
2
<150 ppm to limit silica scale
Sulfides <1 ppm
Sulfur dioxide <50 ppm