Function Of The Pressure Boosting System - Wilo Comfort Co R-Mvi Serie Manual Del Usuario

English
standard with an assembly that can be shut off
with an additional pressure sensor (12) and pres-
sure gauge (11) (see Fig. 5c).
For systems without frequency control (CO – CC),
an assembly for a low-water cut-out switchgear
(WMS) (14) can optionally be installed or mounted
at a later time at the inlet collecting pipe (see
Fig. 5a and 5b).
The control device (2) is mounted directly on the
base frame and ready-wired to the system's elec-
trical components. In the case of larger systems,
the control device is accommodated in a separate
free-standing cabinet (BM) and the electrical
components are pre-wired to the corresponding
connection cable. For the separate free-standing
cabinet (BM) (e.g. Fig. 1c, 1d (2)) the final wiring is
completed by the customer (see Section 7.3 and
the documentation included with the control
device).
The present installation and operating instruc-
tions contain only a general description of the
complete system.
High-pressure multistage centrifugal pumps (1):
Different types of high-pressure multistage cen-
trifugal pumps are installed in the pressure boost-
ing system depending on the application and the
performance parameters required. Their number
can vary from 2 to 6 pumps. Pumps with built-in
frequency converter (Helix VE) or without built-in
frequency converter (Helix V) are used. The
attached installation and operating instructions
provide information on the pumps.
Control device (2):
The CC, CC-FC or CCe series control devices are
used to control and regulate the Wilo-Comfort
pressure boosting system. The size and compo-
nents of the control device may vary depending on
the design and performance parameters of the
pumps. The attached installation and operating
instructions and the corresponding circuit dia-
gram provide information on the control device
installed in this pressure boosting system.
Diaphragm pressure vessel kit (Fig. 2 and 3):
• Diaphragm pressure vessel (9) with flow-through
fixture (10)
Pressure sensor kit (Fig. 2) on the pressure side:
• Pressure gauge (11)
• Pressure sensor (12a)
• Electrical connection for pressure sensor (12b)
• Draining/venting (16)
• Stop valve (17)
Pressure sensor kit (Fig. 5c) on the intake side
(only for COR – CC-FC and CCe systems)
• Pressure gauge (11)
• Pressure sensor (12a)
• Electrical connection for pressure sensor (12b)
• Draining/venting (16)
• Stop valve (17)

6.3 Function of the pressure boosting system

Wilo pressure boosting systems in the Wilo-Com-
fort series are standard-equipped with non self-
priming high-pressure multistage centrifugal
12
pumps, with or without built-in frequency con-
verter. 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 mode
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 sys-
tem.
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 and
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 converter are used, the
speed of one or more of the pumps is changed
until the control parameter settings are achieved.
(A more precise description of the control mode
and the control process is given in the installation
and operating instructions for the control device).
The total delivery volume of the system is distrib-
uted over several pumps. This has the big advan-
tage 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 ensures economical energy con-
sumption 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 for drinking
water supply 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.
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 functions
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 very
small leakages) from the storage volume at hand
without switching on the base-load pump. This
reduces the pumps' switching frequency and sta-
bilises the operating status of the pressure boost-
ing 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 leakages!
For systems with frequency control (COR – CC-FC
WILO SE 07/2017