Pre-adjustable filling units
& backflow preventer
Part # 31070 - 31071
cert. n° 0003
ISO 9001
01061/04 NA
Function
The automatic filling unit is a device consisting of a pressure
reducing valve with compensating seat, an inlet filter, a shut-off
valve and a check valve.
It is installed on the water inlet piping in sealed heating systems,
and its main function is to maintain the pressure of the system
stable at a set value, automatically filling up with water as required.
This product has the characteristic of being pre-adjustable,
which means that it can be adjusted at the required pressure
value before the system charging phase.
After installation, during the filling or topping-off phase, the water
feed will stop when the set pressure is reached.
A pre-assembled version is also available, complete with upstream
backflow preventer.
Product range
Code 31071 Filling unit with pressure gauge and pressure setting indicator Size 1/2”
Code 31070 Charging unit complete with backflow preventer series Size 1/2”
Technical specification
Filling unit
Material: Body: brass
Maximum Working Pressure: 230 psi (16 bar) Pressure
setting range: 3÷60 psi (0.2÷4 bar) Factory setting:
15 psi (1.035 bar)
Indicator accuracy: ±2 psi (±0.15 bar) Maximum
Working Temperature: 150°F (65°C)
Connection: Inlet: 1/2” NPT Male with union tailpiece
Cover: PA 66 GF 30
Seals: NBR
Outlet: 1/2” NPT Female
C US
ASSE 1012
Backflow preventer
Material: Body: brass
Maximum working pressure: 175 psi (12 bar) Maximum
working temperature: 210°F (99°C) Medium: water
Certified to: CSA B64.3 and ASSE 1012
Connections: 1/2”-3/4” NPT female with union
Check valve: PSU
Check valve stem: brass
Diaphragm: EPDM
Seals: EPDM
Code A B C D E
310700
1/2" 1/2” 9” 1
“ 4”
C D A A
D E A
Serie
A
Dimensions
Code A B C D 31071
1/2" 4
“
1
“ 4”
B
13/16
15/16
Construction details
Pre-calibration
This model is equipped with a
pressure setting indicator for
the commissioning operation.
The system charge pressure
can be input by
means of the
adjusting screw,
before the start
of the system
charging phase.
Anti-stick materials
The central housing containing
the moving parts and the internal
compensating spindle are made
of a low adhesion coefficient
plastic. This material minimises
the risk of formation of scale
deposits, the main cause of
malfunctions.
Diaphragm-seat seal
The useful working surface of the diaphragm is particularly large,
in order to guarantee greater precision and sensitivity when
working with minimum pressure differences.
This feature is also
useful in that it
gives greater power
to the sliding of
the spindle and
overcomes friction.
In view of the low flow rates involved, the filling unit seat has been
designed with the smallest possible diameter.
This factor, combined with
the extended surface of
the diaphragm, creates an
optimum dimensional ratio
for a piece of equipment
which must maintain its
operating characteristics
unchanged over time.
psi
CALEFFI
E
PREV
W
BACKF
LO
VENT
C
3/8
Spindle guide
In order to reduce the frictional
surfaces, the spindle unit guide has
been positioned in the upper part of
the device.
It consists of four
spokes formed
directly on the
plastic central
support.
Removable filter cartridge
The cartridge containing the operating mechanisms, protected by
a large surface area strainer, is removable. This makes it very easy
and quick to carry out inspections, internal cleaning and even
replacement of the cartridge itself.
➩
0.3 0.5 2 1 5 2 10 5 20 10 50
15
G
(l/min)
(
gpm
)
Installation
1. Filling unit can be installed in either horizontal or vertical position.
It is, however, vital that the unit is not installed upside down.
2.
The special method of mechanical pre-adjustment with pressure
setting indicator makes it possible to set the unit to the required value
in the system before the beginning of the filling phase.
3.
The unit is normally set at a pressure not less than that obtained by
adding the hydrostatic pressure and 4 psi (0,3 bar).
4.
During filling, the internal mechanism will automatically regulate the
pressure until it reaches the required value,
oversee the filling operation
charged to a higher pressure than required.
itself. This prevents the system being
5.
Given the pre-calibrating function, the presence of the downstream
pressure gauge is not essential.
6.
When the system is filled, the shut-off valve can be closed. In order
to restore the automatic topping-off condition, merely re-open the valve.
The pressure in the system will gradually return to the set pressure.
without the need to
Maintenance
For cleaning, inspection or
replacement of the entire
cartridge, proceed as follows:
2
1.
Isolate the unit.
2.
Open the lower control
knob.
3.
Unscrew the adjusting
screw until it stops.
3
4.
Remove the upper cover.
5.
Extract the cartridge using
pliers.
6.
The entire unit, after
inspection, can be
reassembled or replaced
using a spare cartridge.
5
7.
Re-adjust the equipment.
Backflow preventer
The backflow preventer with atmospheric vent is designed to
protect drinking water systems from the return, caused by
siphonage or backpressure, of contaminated fluids.
The Caleffi 573 series has been specifically certified to standards
CSA B64.3 and ASSE 1012.
➩
VENT
back
Flow rate graph
∆
p
(psi)
20
(psi) (bar)
20
10
5 5
Code 573002A
Charging unit consists of:
- Backflow preventer with intermediate atmospheric vent,
573 series
- Filling unit, 553 series
1
10
0.5
T
BAC
Sizes:
Application diagram
Shut-off valve
Ball valve
Ballstop
Thermometer
Differential by-pass valve
F
Flow switch
Zone valve
T
P
T
F
A
Pump
Autoflow
Flow meter
Temperature probe
T
Safety thermostat
Regulator
Expansion vessel
3-way valve
P
Pressure switch
Control pocket
Gas filter
Gas regulator
Air separator
VENT
A
Fuel shut-off valve
Anti-vibration joint
Sensor pocket
Safety valve
T
Part # 31071
SPECIFICATION SUMMARIES
Filling unit with pressure gauge connection and pressure setting indicator. 1/2” NPT Male with union x Female threaded
connection. Brass body. Nylon plastic cover. Sliding surfaces in anti-stick plastic. Diaphragm and seals in NBR. Cartridge
removable for maintenance operations. Maximum working temperature 150°F. Maximum inlet pressure 230 psi. Setting range
3÷60 psi. Pressure indicator for pre-adjustment of device, accuracy ±2 psi. Complete with isolating valve, filter and check valve.
Part # 31070
Charging unit complete with backflow preventer 1/2” NPT Female with union threaded connection. Maximum working
temperature 150°F. Maximum inlet pressure 175 psi.
We reserve the right to change our products and their relevant technical data, contained in this publication, at any time and without prior notice.
CALEFFI
Infloor Sales and Service
P.O. Box 4945, 503 Gregg Drive, Buena Vista, CO 81211
Tel: 719.395.3400
/
Fax: 719.395-3555 / www.Infloor.com
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