elco RENDAMAX 30, Operating Instructions Manual

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Hot water quality
Hot water quality
The composition and quality of the
system water directly affect the per-
formance of the overall system and the
life of the boiler.
Normally, mains water with a pH value
of 7-8 can be used for the first filling
and subsequent top-ups, provided that
the water is not strongly corrosive
(chlorine content > 150 mg/l) or is very
hard (>14odH; hardness range IV).
A drinking water analysis can be
requested from the appropriate water
supply company.
If the specific system volume is greater
than 20 litres / kW of heat output (e.g.
through the installation of a hot water
buffer tank), the maximum permitted
chalk deposit must be determined by
the filling and top-up water corres-
ponding to the computation of VDI
guideline 2035. If necessary, the water
must be softened. No chemical anti-
corrosion substances must be used.
In Austria,
ÖNORM H 5195-1 also applies.
In Switzerland,
SWKI No. 97-1 also applies.
Unknown water quality and replace-
ment systems
Frequently, substances and additives
are in hot water which impact on the
function and life of the burner.
Therefore, either
x
heat the old system and then fully
empty before replacing,
or
x
carefully rinse the heating system
after replacing. Ideally, the system
should be rinsed directly after the
first heating.
Underfloor heating
For old systems, underfloor heating
systems and if there is problematic
filling water, ELCO recommends fitting
a heat exchanger from the accessories.
Criterion Permissible value Effect of deviation
pH value 7 - 8 Danger of corrosion of boiler components and heating system
Hardness < 14 dH - Increased chalk deposits
- Limited life of boiler
Chlorine content < 150 mg/l Corrosion of alloyed materials
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