Honeywell R295 Einbauanleitung Seite 5

2.3 Checking the Safety Function
● Open an outlet which is downstream of the
backflow preventer
Reduce the inlet pressure to the backflow
●
preventer by slowly closing a shutoff valve on
the inlet side.
☞
The backflow preventer must then go to the
shutoff position at the set pressure
indicated on the rating plate.
The set pressure must be checked by connec-
●
ting a pressure measuring device between the
shutoff valve and the backflow preventer.
These inspections and tests should be carried
out at least once a year by the user or by a
specialist (depending on operating conditions, it
may be necessary to carry out these tests and
inspections more frequently).
3. The Correct Opening Pressure
The set pressure of the backflow preventer is
determined by the maximum pressure which will
occur in the downstream system. It must be at
least 0.5 bar higher than the pressure in the system
to be protected.
If the highest possible dirty water level in the system
to be protected or the highest takeoff point are 10
metres above the installation location of the
backflow preventer, then the set pressure must
be greater than or equal to 1.5 bar. The backflow
preventer begins to go to the shutoff position if the
inlet pressure falls to the set pressure (in this
example, 1.5 bar).
6.Technical Data
Scope of application:
Inlet pressure:
Installation position:
Operating temperature:
Opening pressure:
Minimum inlet pressure:
Connection Size
Nominal flow rate (m
k -value (full flow)
vs
ζ-value
Drinking water
max 16.0 bar
Horizontal with spring bonnet upwards
Up to 40°C
0.5; 1.0; 1.5 or 2.0 bar as required.
Set pressure + 0.5 bar
Rp
3 /h) atΔp = 0,3 bar
GB
Set pressure pa >= 0.5 bar. In addition it must
also correspond to the following:
1. The pressure H corresponding to the height of
the highest takeoff point in the downstream
system.
2. The maximum pressure pa permissible in the
the appliance or system.
The higher the set pressure, the sooner the
shutoff position will be reached.
4. The Correct Construction Type
As well as the choice of the correct set
pressure, the selection of the right construction
type also determines the degree of protection
provided.
Construction Type: R 295/R 295-F.
Backflow preventer normally in the flow position.
Goes to shutoff position only when the inlet
pressure falls below the set pressure.
Installation areas and construction types are
specified in the EN 1717; Protection against
pollution of potable water installations and
general requirements of devices to prevent
pollution by backflow.
5. Maintenance
Honeywell backflow preventers are safety
devices which require very little maintenance
and which are installed to prevent backflow of
uncleaned water into the supply network, into
separate systems or into other sections of an
installation. Depending on operating and flow
medium conditions, to ensure trouble free
operation it is necessary at fixed time intervals to
check seal components, piston guides and
rating springs and where necessary replace
them.
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