Table of Contents
Advertisement
(inhibitors or anti-corrosion agents) can damage the heat generator and
heating system.
▶ Only fill the heating system with potable water. Do not use well- or
groundwater.
▶ Determine the water hardness of the filling water, before filling the
system.
▶ Flush the heating system prior to filling.
▶ If magnetite (iron oxide) is present, anti-corrosion measures are
required and the installation of a magnetite separator and a de-airing
valve in the heating system is recommended.
For German market:
▶ The fill and top-up water must meet the requirements of the German
Drinking Water Ordinance (TrinkwV).
For markets outside Germany:
▶ The limit values in table 6 must not be exceeded, even if national
directives contain higher limits.
Water quality
Unit
Conductivity
μS/cm
pH
Chloride
ppm
Sulphate
ppm
Sodium
ppm
Table 6 Boundary conditions for potable water
▶ Check the pH value after > 3 months of operation. Ideally at the first
service.
Material of heat
Heating water
generator
Ferrous, Copper,
•Untreated potable water
copper brazed
•Fully softened water
heat exchangers
• Low-salt operation < 100 μS/
cm
Aluminium
•Untreated potable water
• Low-salt operation < 100 μS/
cm
1) If pH value is < 8.2 an on-site test for ferrous corrosion is necessary
Table 7 pH value ranges after > 3 months of operation
▶ Treat the fill and top-up water according to the instructions in the
following section.
Depending on the hardness of the filling water, the system water volume
and the maximum heat output of the heat generator, water treatment
may be required to avoid a damage in water heating installations, due to
the formation of lime scale.
Requirements on the fill and top-up water for heat generators made
of aluminium and Heat pumps.
Compress 5800i AW – 6721858460 (2023/06)
y
Fig. 8
Value
[x]
≤ 2500
[y]
≥ 6,5... ≤ 9,5
≤ 250
[1]
≤ 250
[2]
≤ 200
For systems with a specific system water content >40 l/kW, water
treatment is mandatory. If there are several heat generators in the
pH value range
heating system, then the system water volume must be related to the
heat generator with the lowest output.
1)
7.5
– 10.0
A recommended and approved method for water treatment is
1)
7.0
– 10.0
desalination of the fill and top-up water to a conductivity of ≤ 10 μS/cm.
Instead of water treatment, system separation with a heat exchanger,
1)
7.5
– 9.0
directly after the heat generator, can be provided.
1)
7.0
– 9.0
Prevention of corrosion
In most cases, corrosion plays only a minor role in heating systems.
However, a precondition for this is that the system is a corrosion-sealed
water heating installation. This means that there is practically no access
of oxygen to the system during operation. Continuous introduction of
oxygen leads to corrosion and can thus cause rusting and rust sludge
formation. Sludge formation can not only cause blockages and therefore
a diminished heat supply but also deposits (similar to lime scale
deposits) on the hot surfaces of the heat exchanger.
The amount of oxygen introduced by the fill- and top-up water are
generally very small and can therefore be ignored.
To avoid oxygenation, connection pipes must be diffusion-tight!
The use of rubber hoses should be avoided. The intended connection
accessories should be used in the installation.
During operation, pressure maintenance with regard to oxygen ingress
and in particular the function, correct sizing and correct setting (pre-
charge pressure) of the expansion vessel is of highest importance.
Check the pre-charge pressure and function annually.
Furthermore, the function of automatic air vents should also be checked
during maintenance.
It is also important to check and document the top-up water quantities
via a water meter. Larger and regularly required water top-up quantities
indicate insufficient pressure maintenance, leaks or continuous oxygen
input.
Antifreeze
3,00
2,80
< 100 kW
2,60
< 50 kW
2,40
2,20
2,00
1,80
1,60
1,40
1,20
1,00
0,80
2
0,60
0,40
0,20
0,00
0
5
10
x
Heat generators < 50 kW-100 kW
Total hardness in °dH
Maximum possible water volume over the service life of the heat
3
source in m
Above the curve, only use desalinated fill and top-up water, with a
conductivity of ≤ 10 μS/cm
Below the curve, untreated fill and top-up water according to
drinking water regulation can be used
Preparing for installation
1
15
20
25
30
0010048707-001
11
Advertisement
Table of Contents
