5 Installation
5.1 Requirements for the heating water
The central heating water must comply with VDI Guideline 2035 or similar local reg-
ulations.
▪
Untreated fill and top-up water must be of domestic water quality (colourless, clear
and without sedimentation),
▪
the fill and top-up water must be pre-filtered (mesh max 25 µm),
▪
the pH value must be 8.5 ± 0.5,
▪
there must be no oxygen enrichment of the heating water (max 0.05 mg/l),
▪
in the case of diffusion resistant system components, the unit must be de-coupled
from the heating circuit by means of a separator.
5.1.1 Water hardness
The admissible water hardness is determined in relation to the fill water quantity.
▶
Determine from the diagram below whether water treatment measures are neces-
sary.
If the fill water lies in the range above the curve:
▶
treat the fill and top-up water.
Fill water volumes < 300 litres and within the range below the limit curve need not be
treated.
300
400
500
600
700
900
800
0
2
4
6
8
10
12
14
18
20
16
1
Fill water volume [litres]
2
Total hardness [°dH]
5.1.2 To-up water volume
▶
Record the fill and top-up water quantities in the system logbook.
If the quantity of top-up water exceeds twice the volume of the contents of the system:
▶
Treat the fill and top-up water as a basic principle (irrespective of the water hard-
ness).
Installation and operating instruction
Hydraulic unit WWP L 7 ... L 15
5 Installation
83279602 • 1/2014-05 • La
23-59
