23
Definition of water types
Drinking water
- Tap water, in conformity with the
European
Drinking Water Directive: 98/83/EC,
dated 3 November 1998.
Softened water
- Water, from which calcium and
magnesium ions have been
partially removed.
Demineralized water
- Water, from which almost all salts
have been removed (very low
conductivity).
Distilled water
- Water, in which no more salts are
present
Water quality for DHW facilities
- When the amount of chloride is
above the required specifications
mentioned above in table 2, in case
of the use of a combi boiler will void
the warranty for DHW parts of the
boiler.
Parameters
Value
Water type
Drinking water
pH
7.0-9.5
Conductivity (at 20°C in µS/cm)
Max 2500
Chloride (ppm)
Max 150
Iron (ppm)
Max. 0.2
Hardness (°dH / °fH)
1-12
Number of bacteria colonies at 22°C (number/ml) according
to EN ISO 6222
Max. 100
Table 2
Installation
Water and hydraulic system
DHW quality
Expansion vessel
The CH-installation has to be fitted with
an expansion vessel. The expansion
vessel used has to comply with the
water contents of the installation.
It is not necessary to install an
expansion vessel to each boiler. One
single, central installed expansion
vessel is sufficient. When using a
single expansion vessel the handles of
the valves on the flow and return pipes
below the boiler have to be removed
whilst open.
A boiler expansion vessel can be
connected on the cross union inside
the return pipe to each boiler, if
required. The connection is fitted with a
3/4” outer thread blanking cap.
Expansion DHW cylinder circuit
When applying a DHW cylinder
connected directly to the boiler
(Rendamax cylinder connection
with use of 3-way valve) the circuit
between the three-way valve and the
separation of the DHW cylinder should
be provided of an expansion tank. See
also page 26.
Expansion vessel
