Function Of The Pressure-Boosting System - Wilo SiBoost Smart Série Notice De Montage Et De Mise En Service

Pressure diaphragm pressure vessel kit
(Fig. 3 or Fig. 5):
• Diaphragm pressure vessel (9) with flow-through
fixture (10)
Pressure sensor kit on the pressure side
(Fig. 2a and 2b)/ for systems with frequency
control of every pump (SCe) also on the intake
side (Fig. 6d and 6e):
• Pressure gauge (11)
• Pressure sensor (12)
• Electrical connection for pressure sensor (12b)
• Draining/venting (16)
• Stop valve (17)

6.3 Function of the pressure-boosting system

SiBoost Smart series Wilo pressure-boosting sys-
tems are fitted as standard with non self-priming
high-pressure multistage centrifugal pumps with
or without built-in frequency converters. These
are supplied with water via the inlet collecting
pipe.
Where self-priming pumps are used for special
versions, or generally in the case of suction from
lower-lying tanks, a separate vacuum-proof and
pressure-resistant suction line with a foot valve
must be installed for each pump. The line must rise
continuously from the tank to the system.
The pumps increase the pressure and pump the
water to the consumer via the pressure collecting
pipe. To do this, they are switched on and off or
controlled depending on the pressure. The pres-
sure sensor continuously measures the actual
pressure value, converts it into a current signal and
transmits it to the control device.
Depending on the requirement and the control
mode, the control device switches the pumps on,
switches them in, or switches them off. If pumps
with built-in frequency converters are used, the
speed of one or more of the pumps is changed
until the control parameter settings are achieved.
(The control modes and control processes are
described in detail in the greater detail in the
control device's installation and operating
instructions.)
The total delivery volume of the system is distrib-
uted over several pumps. This has the significant
advantage that the system output is adapted very
precisely to the actual demand and the pumps are
operated in the most favourable performance
range in each case. This design delivers a high level
of efficiency and an economical energy consump-
tion for the system.
The first pump that starts up is called the base-
load pump. The remaining pumps needed to reach
the system operating point are called peak-load
pump(s). If the system is configured to supply
drinking water according to DIN 1988, one pump
must be designated as a standby pump, i.e. at
maximum extraction, one pump is always decom-
missioned or on stand-by.
Installation and operating instructions Wilo-SiBoost Smart (FC) ... Helix V/... Helix VE/... Helix EXCEL
To ensure that all the pumps are used equally,
the control unit cycles the pumps continuously,
i.e. the order of switching on and the allocation of
the base load/peak load or standby pump func-
tions change regularly.
The diaphragm pressure vessel installed (total
capacity of approx. 8 litres) exercises a certain
buffer effect on the pressure sensor on the pres-
sure side and prevents oscillation of the control
when switching the system on and off. It also
guarantees low water extraction (e.g. for smallest
leakage) from the storage volume at hand without
switching on the base-load pump. This reduces
the pumps' switching frequency and stabilises
the operating status of the pressure-boosting
system.
CAUTION! Risk of damage!
To protect the mechanical seal or plain bearings,
do not allow the pumps to run dry. Dry running
can lead to the pump developing leaks!
On systems with frequency control of every single
pump (SCe), the pressure sensor on the intake side
monitors the supply pressure and transmits this as
a current signal to the control device. If the supply
pressure is too low, the system detects a fault and
the pumps are stopped. (For a more detailed
description, see the installation and operating
instructions for the control device).
For systems without frequency control of every
pump (SC and SC-FC), various kits are offered as
accessories for direct connection to the public
water mains as protection against low water level
(WMS) (14) (Fig. 6a and 6b). Each kit incorporates
a built-in pressure switch (22). This pressure
switch monitors the supply pressure and if the
pressure is low it sends a switching signal to the
control device.
An installation point for this purpose is provided as
standard at the inlet collecting pipe.
In the case of an indirect connection (system sep-
aration by non-pressurised break tank), a level-
dependent signal transmitter must be provided
and installed in the break tank as a dry-running
protection device. If a Wilo break tank is installed
(as in Fig. 13a) a float switch is already included in
the scope of delivery (see Fig. 13b).
For existing on-site tanks, you will find various
signal transmitters in the Wilo range that can be
retrofitted (e.g. float switch WA65 or low water
warning electrodes with level relay).
WARNING! Health hazard!
Only materials that have no adverse effects on
the quality of the water may be used for drink-
ing water systems!
English
13