Importance of water quality
The selection of corrosion protection type in a hot water vessel is often dependent on what has been used traditionally in a certain area but a very important factor is also the water quality.
There are certain requirements regarding the properties of most municipal water such as a pH-value within a fixed range, which is why one of the three corrosion protection types, copper, enamel or stainless steel, can normally be used in a hot water vessel.
As regards wells and local water supplies the composition of the water varies from place to place.
Answers from water analysis
The corrosion properties of water are dependent on the amounts of the constituent substances and how they cooperate with each other. An evaluation of the water quality can be only done after an analysis. NIBE can provide such an analysis for their customers to select the suitable type of corrosion protection. In certain cases it can be necessary to install a filter to obtain an acceptable water quality.
Factors that affect the water
pH-value
The pH-value is also called acidity and is a measurement of the
content of hydrogen ions in the water. Waters with low pH-values
are aggressive and dissolute among others metals.
Total hardness
A measurement of the amount of calcium and magnesium. Is
often measured in German hardness degrees (dH°), or as mg/l
calcium.
Aggressive carbon dioxide
This is the part of the free carbon dioxide that has etching
properties. The presence of aggressive carbon dioxide in combination
with low pH- and/or hardness values makes the water
aggressive.
Chloride content
High content of chloride can create an aggressive water, especially
if there is a tendency of lime deposit.
Conductivity
A measurement of the content of dissolved salts such as chlorides and
sulphates in the water.