Commissioning; Softened Water Volume Calculation; Calculations Before Initial Filling - STIEBEL ELTRON HZEA Installation

INsTALLATIoN

Commissioning

6. Commissioning
f In the system manual provided, make a note of the date of
commissioning and the current status of the water meter
fitted on site.
f Make a note of the meter reading at which the next filter
change will be required. Calculate the value by adding
the softened water volume to the current water meter
reading.
6.1

Softened water volume calculation

You can ask the local water supply utility to tell you the total
water hardness value at the place of use; there is no charge
for this.
f Calculate the softened water volume:
� � � �
�
���
V softened water volume
WWM
GH Total water hardness at the place of use
Ist
Example
The heating system has a system volume of 2000 l (e.g. total
heating output of 180 kW with radiators). The regional water
supply utility informs you that the total hardness is 20 °dH. This
gives a softened water volume (0 °dH) of 300 l. With an annual
top-up volume of approx. 10 % of the system volume (in this
example 200 l), the filter cartridge is generally sufficient for
1.5 years.
Notice
The top-up water must generally be softened to 0 °dH.
f Check the final water level regularly.

6.2 Calculations before initial filling

Up to a heating output of approx. 100 kW, initial filling can be
carried out directly via the water softening device (see chapter
"Commissioning / Initial filling"). Replace the cartridge after
initial filling (see chapter "Commissioning / Initial filling / Re-
placing the filter cartridge").
For initial filling, an appropriate number of cartridges is re-
quired, depending on the system volume. The volumes of the
buffer cylinder, low loss header, etc. should be taken into ac-
count in the system volume.
If the system was flushed with unsoftened water, it must be
completely flushed with softened water. More cartridges may
be required.
HZEA
6000 � ����� �
� ��� �
��
���
6.2.1 Calculating the number of cartridges
We recommend softening to 0 °dH.
f Calculate the number of cartridges for initial filling using
the following equation:
� ��
�
� �
� ���
6000 � � � ��� �
��
N Number of cartridges
PA
V system volume
A
GH Total water hardness at the place of use
Ist
GH Required total water hardness
soll
f Round up the calculated value to determine the required
number of cartridges for initial filling.
6.2.2 Calculating the system volume
If the system volume is unknown, it can be determined approx-
imately by means of the total heating output and the table
below.
Air heating coil
Panel radiators
Modern radiators
Column radiator
Underfloor heating
6.2.3 Calculating the water volume per cartridge
The water volume used to fill the heating system per cartridge
corresponds to the system volume divided by the number of
cartridges required. You can keep an eye on the fill volume via
the water meter.
once the filling process is complete, a new cartridge is inserted.
The new cartridge will soften the top-up water in future.
Water volume per car-
tridge
�� � ��� �
� ��
����
Specific system capacity
l/kW
l/kW
l/kW
l/kW
l/kW
system volume V
A
Number of cartridg-
es N
PA
7
8.5
11.2
17.0
20
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