Liebert XDK-W user manual Appendix Quality requirements on the water used in CoolTherm

CoolTherm

Manual / Bedienungsanleitung

9.Appendix

9.1Quality 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

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