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Manual / Bedienungsanleitung
CoolTherm 01_998_330_0_k page / Seite 33/83
9. Appendix
9.1 Quality requirements on the water used in CoolTherm
To ensure the maximum service life of air-water heat exchangers, chilled water must comply with
the VGB chilled water regulations (VGB-R 455 P). Chilled water used must be soft enough to
prevent deposits, but must not be so soft that heat exchanger corrosion occurs.
The following table contains the most important impurities and methods for removing them:
Water impurity Method of removal
Mechanical pre-treatment (dp < 1 mm) Filtering the water
Excessive hardness Soften the water using ion exchange
Moderate content of mechanical impurities and hardness formers Addition of dispersing agents or stabilising
agents
Moderate content of chemical impurities Addition of passivation agents and
inhibitors
Biological impurities (bacteria and algae) Addition of biocides
It is recommended to achieve the following hydrological data as far as possible:
Hydrological data
pH values
>7
Carbonate hardness
>3 <8 °dH
Free carbon dioxide
8 - 15 mg/dm3
Bound carbon dioxide
8 - 15 mg/dm3
Aggressive carbon dioxide
0 mg/dm3
Sulphides
< 10 mg/dm3
Oxygen
< 50 mg/dm3
Chloride ions
< 250 mg/dm3
Sulphate ions
< 10 mg/dm3
Nitrates and nitrides
< 7 mg/dm3
CSB
< 5 mg/dm3
Ammonia
< 5 mg/dm3
Iron
< 0.2 mg/dm3
Manganese
< 0.2 mg/dm3
Conductivity
< 30 µS/cm
Solid evaporation residue
< 500 mg/dm3
Potassium permanganate consumption
< 25 mg/dm3
Suspended matter
< 3 mg/dm3
(Partial flow cleaning is recommended)
> 3 < 15 mg/dm3
(Continuous cleaning)
> 15 mg/dm3