Engineering information and sizing the heat source
6 720 645 817
(2010/09)
38
Water treatment measures
There are two methods for treating the fill and top-up
water for Suprapur gas condensing boilers:
•
Use of fully desalinated fill water with a conductivity
of
≤
10
μ
S/cm:
During the total desalination of the fill and top-up
water, not only the causes of hardness (Ca, Mg) but
also all other minerals are removed. This significantly
reduces the conductivity of the fill and top-up water.
The likelihood of corrosion forming shrinks as the con-
ductivity of the heating water drops. Operation with a
low salt content will at the same time reduce corro-
sion in the heating system.
•
Use of partially softened fill and top-up water based
on sodium ion exchangers:
The fill and top-up water must have a residual
hardness of 5 °dH to 7 °dH.
Only use chemicals approved by Junkers.
Additional protection against corrosion
Damage through corrosion occurs if oxygen constantly
enters the heating water, for example through
inadequately sized or faulty expansion vessels (MAG) or
open vented systems.
If a sealed unvented heating system is not feasible,
corrosion protection measures are required, e.g. by
adding approved chemicals or by system separation
through the use of a heat exchanger.
Installation in existing heating systems/dirt traps
If the gas condensing boiler is installed in an existing
heating system, impurities may build up in the boiler,
leading to local overheating, corrosion and noise.
We therefore recommend the installation of a dirt trap
and blow-down facility. This should be installed
immediately between the boiler and the lowest position
with good accessibility, and should be cleaned during
every service.
Estimate of system capacity
Especially with older systems, the water capacity of the
entire system is often not known. The following graph
gives an estimate of the system capacity.
Fig. 24 Estimated water capacity of the system with
known system output
Q
Total system output
V
Water capacity
1
Steel/cast iron radiators with pipes sized for gravity
circulation and underfloor heating (20 l/kW)
2
Panel radiators (10 l/kW)
3
Convectors (6 l/kW)
0
1
2
3
4
5
6
7
8
9
10
11
12
0
100
200
300
400
500
600
1
2
3
V [m
3
]
Q
[kW]
6 720 642 877-13.1il
.
Содержание SUPRAPUR KBR 120-3 A
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