Function - Wilo VBH 150 L Notice De Montage Et De Mise En Service

The tank is equipped with a draw-off connection
(3) which enables connection with a pressure
boosting system and which is designed as either a
threaded bushing or a loose flange, depending on
the type and size of the tank. The precise align-
ment and size of the connection can be found in
the respective drawing (Figs. 1a to 1h). A threaded
connection which is sealed with a plug is fitted on
all of the tanks for drainage purposes (4). All tanks
are equipped with a water level indicator in the
form of a clear-view tube (5). This clear-view tube
is fastened to the interior of the tank at the time
of delivery in order to avoid damage. It must be
installed with the aid of the screwed connections
(6) provided for fastening it before the tank is
filled for the first time (Fig. 2)
Each tank is equipped with one or more overflow
connections (7) which protect the potable water
supply network by preventing the water in the
tank from flowing back into it. These are designed
in a variety of ways, depending on the type and
installation size. The cover of each tank is
equipped with a ventilation and exhaust feature
(8) with a corrosion-resistant strainer which keeps
insects out of the tank. A threaded connection (9)
is also to be found on the cover which can be used
for connecting an optional flushing apparatus (Fig.
3-(32)) for the potable water inlet. An inspection
opening with a cover (10), which is sealed with a
locking ring, provides access to the interior of the
tank for cleaning and maintenance work. A variety
of different plates and walls are on hand in the
interior of the tank which are used as wash plates
for calming the fluid.
In every tank there is a float switch (11) which acts
as a low-water signal transmitter for the pressure
boosting system that is to be connected. This is
fastened to a plastic tube through which the con-
necting cable is guided upwards. The cable is
guided through the tank cover by means of a
threaded cable connection and ends in a damp-
proof connection socket (12). The cable ends are
guided onto a terminal strip which is used for fur-
ther connection to the terminals of the pressure
boosting system control device provided for that
purpose (see electrical connection).

6.2 Function

The Wilo break tank is a closed break tank under
atmospheric pressure in accordance with DIN1988
for the purpose of indirectly connecting a pressure
boosting system to the public potable water net-
work. It is used for holding a particular useable
volume of potable or process water. The nominal
tank volume required for a pressure boosting sys-
tem depends on the volume flow required and the
supply pressure available. The precise configura-
tion is to be undertaken in accordance with stand-
ard specifications (DIN1988 or other locally
applicable regulations). If the water supply is suf-
ficiently guaranteed by the water supply company
(WVU), then a simple determination of the size of
the necessary useable volume can be approxi-
Installation and operating instructions Wilo-VBH
mated with the formula VB = 0.03 x VmaxDEA (VB
= tank volume; VmaxDEA = maximum volume
flow of the pressure boosting system).
The water is fed into the break tank from the
water supply network through an inlet valve which
opens and closes, depending on the level (float
valve or diaphragm valve as separate accessory).
The intake of water will be interrupted when the
water level in the tank reaches the closing level
which has been set for the valve. The water con-
tained in the tank is channelled to the pressure
boosting system via the draw-off connection of
the break tank. When the pressure boosting sys-
tem is switched on by its control unit in accord-
ance with requirements, the necessary amount of
water is extracted from the tank and fresh water is
brought in through the inlet valve accordingly.
Tanks are equipped with overflow connections to
protect the water supply network by preventing
the water in the tank from flowing back into it. In
the case of types GII and GIII, the overflows are
present as circular cross-sections (type AF DIN EN
1717) with sockets (Fig. 6a). Here it must be
ensured at the time of connection that the water
can flow out freely. No direct linkups between the
overflow and the sewage network are permitted.
In the case of tanks of the FLA type, the overflow
is designed in the form of a noncircular cross-sec-
tion, which is protected by a moving shutter
against the intrusion of small animals and dust.
The water can run out freely through this overflow
and then be drained off through the collection
housing on the pipe connection located below.
Commercially available drain pipes with HT plug
couplers (high-temperature plug couplers made
of polypropylene) of the respective nominal diam-
eter can be fitted to this pipe connection (Fig. 6b).
In the event that sufficient amounts of water can-
not be drained off through this connection, the
collection housing acts as an emergency spillway,
i.e. the water runs off over the walls of the hous-
ing. This ensures that no backflow is permitted to
build up at the inlet valve.
CAUTION
! Overflowing water could cause
material damage!
In order to avoid water damage, a sufficiently
dimensioned floor drainage system must be
present in the room where the equipment is
installed!
The retrofitting of an overflow alarm device and of
an alarm switchgear that emits a visual or acoustic
signal is recommended for signalling a tank over-
flow.
In order to protect the pressure boosting system
against low water in the tank or even against the
dry-running of the pumps, a float switch (11) is
installed in the tank in such a way (see Fig. 7) that
a switching signal is sent to the pressure boosting
system control unit when a minimum permissible
water level is reached (Fig. 7, lower position (14)).
The system must then be switched off by the reg-
ulator following the expiration of a time delay
English
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