Chicago Pneumatic CPF 270, Instruction Book

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recommendations formulated in our Cooling Water Specifications are a general guide line for acceptable
coolant quality. However, where strict limits apply, a statement is made in the specification.
The water requirements refer to untreated water. When water is treated, some parameters will change. Water
treatments should be carried out by a specialized water treatment company, taking the responsibility for the
performance of the treated cooling water and the compatibility with the materials in the cooling circuit. This
includes not only the selection of the appropriate additives, but also the correct application, monitoring of
concentrations and properties, prevention of sludge formation and maintenance of the system. This applies
also to treatment with antifreeze products. They must be provided with suitable stabilizers and inhibitors.
Specifications are also depending on the type of cooling circuit (open, once through / recirculating with tower /
closed) and on the application (Standard – max 65 °C cooling water temperature at the outlet) or Energy
Recovery (water temperature up to 95 °C).
In case water is not in line with recommended values or if any doubt, consult the manufacturer.
Cooling water parameters
1. pH
The effect of pH is already included in the Ryznar Stability Index (RSI - see item 4 below), but also the
pH itself is subject to limitations:
pH
Type of cooling system Materials Standard Energy recovery
Single pass Containing copper 6.8 - 9.3 6.8 - 9.3
Stainless steel with carbon
steel and / or cast iron 6.8 - 9.3 6.8 - 9.3
Stainless steel only 6 - 9.3 6 - 9.3
Recirculating (with tower) Containing copper 6.8 - 9.3 not applicable
Stainless steel with carbon
steel and / or cast iron 6.8 - 9.3
Stainless steel only 6 - 9.3
Closed loop Containing copper 7.5 - 9.3 7.5 - 9.3
Stainless steel with carbon
steel and / or cast iron 7.5 - 9.3 7.5 - 9.3
Stainless steel only 6 - 9.3 6 - 9.3
The values in bold are rejection limits.
When the system contains Zn or Al, the pH must be < 8.5.
2. Total dissolved solids (TDS) and conductivity
The conductivity is expressed in μS/cm, the TDS in ppm.
Both parameters are related with each other. The conductivity is convenient for quick monitoring of general
water quality, but the TDS is required for calculating the RSI. If only one of both parameters is measured,
an estimation can be obtained by using a theoretical conversion factor (0.67):
TDS = conductivity x 0.67
3. Hardness
Different types of hardness are in relation with each other and together with the pH and the alkalinity of
the water they determine the equilibrium situation of the water, determined and specified by the RSI.
In addition, the calcium hardness must be limited to:
Instruction book
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