• In the case of an indirect connection, i.e. for oper-
ating with the customer's tanks:
fit the float switch in the tank so that if the water
level drops to approximately 100 mm above the
draw-off connection, the "low water" switching
signal is transmitted. (If break tanks from the
Salmson range are used, a float switch is already
installed (Fig.b13a and 13b).
• Alternatively: install submersible electrodes in the
break tank. The arrangement is as follows: a 1st
electrode is installed just above the floor of the
tank as an earth electrode (must always be sub-
merged) and for the bottom switching level (low
water) a 2nd electrode is installed approximately
100 mm above the extraction connection. For the
upper switching level (no longer low water) a third
electrode should be fitted at least 150 mm above
the lower electrode. Connect the wiring to the
control device according to the installation and
operating instructions and wiring diagram of the
control device.
7.2.5 Diaphragm pressure vessel (accessory)
The 8-litre diaphragm pressure vessel available as
an optional addition to the scope of delivery of the
pressure boosting system (only with Nexis V or VE)
pumps may for transport technical and hygiene
reasons be supplied as a separate unfitted part.
The diaphragm pressure vessel must be mounted
on the throughflow valve before commissioning
(see Fig.b2a and 3).
NOTE
When doing this, ensure that the throughflow
valve is not twisted. The fitting is correctly
mounted when the drain valve (see also Fig. 3) or
rather the flow direction arrows stamped on it are
parallel to the manifold pipe.
A diaphragm pressure vessel is available as a ret-
rofit kit accessory to a system with pumps of the
Nexis advens (with casing!) series. Under unfa-
vourable operating conditions such as may require
Nominal diameter
Connection
3
Max. volume flow (m
/h)
Table 1
7.2.6 Safety valve (accessory)
A component-tested safety valve must be
installed on the discharge side if the sum of the
maximum possible supply pressure and the maxi-
mum delivery pressure of the pressure boosting
system can exceed the admissible positive oper-
ating pressure of an installed system component.
The safety valve must be designed so that it will
drain off the volume flow occurring in the pressure
boosting system when the positive operating
pressure is 1.1-times the admissible level (design
data are given in the data sheets/characteristic
curves of the pressure boosting system).
Installation and operating instructions Alti-Nexis V/-Nexis VE/-Nexis advens
DN 20
DN 25
DN 32
(Rp ¾")
(Rp 1")
(Rp 1¼")
2,5
4,2
the provision of a diaphragm pressure vessel, it
can be fitted by means of the respective retrofit
kit (see Fig.b5). This kit is connected to the pres-
sure side system pipes of the pressure boosting
system using the threaded pipe union supplied as
part of the retrofit kit.
If an additional larger diaphragm pressure vessel
must be installed, follow the corresponding instal-
lation and operating instructions. In the case of a
potable water installation, a throughflow dia-
phragm pressure vessel according to DIN 4807
must be used. When installing a diaphragm pres-
sure vessel, also make sure there is enough room
for maintenance work or replacement.
NOTE
Diaphragm pressure vessels require regular test-
ing according to directive 97/23/EC
Check valves must be provided upstream and
downstream of the vessel for tests, overhaul and
maintenance work on the pipe. To prevent system
downtime, connections for a bypass can be fitted
before and after the diaphragm pressure vessel.
Such a bypass (as for example in the diagram Fig.b7
andb8 itemb33) must be completely removed after
completion of the work, so as to avoid stagnation
of the water! Special maintenance and test
instructions are given in the installation and oper-
ating instructions of the diaphragm pressure ves-
sel concerned.
The installation conditions and delivery specifica-
tions of the system must be taken into account
when selecting the size of the diaphragm pressure
vessel. When doing so, ensure there is sufficient
flow through the diaphragm pressure vessel. The
maximum volume flow of the pressure boosting
system must not exceed the maximum admissible
volume flow for the diaphragm pressure vessel
connection (see Table 1 or the specifications on
the rating plate, and the installation and operating
instructions of the vessel).
DN 50
DN 65
Flange
Flange
7,2
15
27
The water that flows off must be safely drained
away. The corresponding installation and operat-
ing instructions and the relevant conditions must
be observed during the installation of the safety
valve.
7.2.7 Non-pressurised break tank (accessory)
To connect the pressure boosting system indi-
rectly to the public drinking water mains, it must
be installed together with a non-pressurised
break tank according to DIN 1988. The rules for
the pressure boosting system apply to the instal-
lation of the break tank as well (see 7.1).
English
DN 80
DN 100
Flange
Flange
36
56
41