Bosch Compress 7400i AW Installer's Manual page 4

Regulations
If the limits for water hardness stated in table 2 are exceeded, the
performance of the heat pump will deteriorate over time. If this
performance degradation can be accepted, the limits in figure 1 are
required to ensure the operation of the heat pump throughout its entire
life span.
Heat pump Total alkalinity
output [kW] / total hardness
of the filling
water [°dh]
Q < 50 Requirements
according to
figure 1
Table 4 Table for heat pumps
3
V [m ]
2,60
2,40
2,20
2,00
1,80
1,60
1,40
1,20
1,00
0,80
0,60
0,40
0,20
0,00
0 5
Fig. 1 Limits for water treatment in heat pump systems
A Use completely de-mineralized fill water above the curve,
conductivity ≤ 10 microsiemens /cm.
B Use untreated tap water below the curve. Fill according to the
drinking water regulation.
H Water hardness.
w
V Total water volume: Fill volume of the heating system and top-up
volume over the life span of the heat pump.
If the total water volume is above the limit curve in the diagram (Fig. 1)
suitable measures are required for water treatment.
Suitable measures are:
• Use of fully de-mineralized fill water with a Conductivity of ≤ 10
microsiemens / cm.
To prevent oxygen from entering the heating water, the expansion vessel
must be adequately dimensioned.
When installing diffusion open pipes, a system separation with the help
of a heat exchanger is required.
4
Maximum fill and top-up water
3
volume V [m ]
max
Requirements according to
figure 1
A
B
10
H [°dH]
W
0010036248-002
15
Compress 7400i AW – 6721833372 (2021/09)