Liebert XDK User Manual

To ensure the maximum service life of the air/water heat exchangers, water must comply with the 

VGB water regulations (VGB-R 455 P). The water used must be soft enough to prevent deposits, but it 

must not be so soft that heat exchanger corrosion occurs.
The following table contains the most important impurities and methods for removing them.

It is recommended to achieve the following hydrological data as far as possible:

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 or stabilizing agents

Moderate content of chemical impurities

Addition of passivation agents and inhibitors

Biological impurities (bacteria and algae)

Addition of biocides

pH values

7 - 8.5

Carbonate hardness

>3 <8 

°dH

Free carbon dioxide

8 - 15

mg/dm

3

Bound carbon dioxide

8 - 15

mg/dm

3

Aggressive carbon dioxide

0

mg/dm

3

Sulfides

< 10

mg/dm

3

Oxygen

< 50

mg/dm

3

Chloride ions

< 250

mg/dm

3

Sulfate ions

< 10

mg/dm

3

Nitrates and nitrides

< 7

mg/dm

3

CSB

< 5

mg/dm

3

Ammonia

< 5

mg/dm

3

Iron

< 0.2

mg/dm

3

Manganese

< 0.2

mg/dm

3

Conductivity

< 2200

μS/cm

Solid evaporation residue

< 500

mg/dm

3

Potassium permanganate consumption

< 25

mg/dm

3

Suspended matter

< 3

mg/dm

3

(Partial flow cleaning is recommended)

> 3 < 15 

mg/dm

3

(Continuous cleaning)

> 15

mg/dm

3