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MAX PRESSURE SLAM SHUT OFF VALVE
Technical Specifications
Connection: threaded UNI EN 10226-1; flanged PN16 EN
1092-4
Maximum inlet pressure: 1 bar (MB); 6 bar (MB/6B)
Ambient temperature: -10°C÷+60°C
Response pressure: blue spring: 30÷120 mbar;
neutral spring: 80÷550 mbar
Max surface temperature: 60°C
Fuel: all three families of gas (city gas, methane, LPG); non
aggressive gases.
Material: aluminium valve's body and cover; stainless steel
springs and control piston; NBR rubber basket and O-ring;
other part are of brass, aluminium and galvanised steel.
General information
The maximum pressure slam shut off valves in the MB and
MB/6B series are safety devices kept open under normal work
conditions thanks to an automatic mechanism triggered upon
manually rearming. If the shut off plenum detects an inlet pres-
sure greater than the calibration value, it releases the closure
device which stops the gas flow.
Installation
The maximum pressure slam shut off valves MB - MB/6B
conform to Directive 2014/34/UE (ATEX) in group II category
2G and in group II, category 2D; as such they are suitable for
installation in zones 1 and 21 and, even more so, in zones 2
and 22 as classified in enclosure I of Directive 99/92/EC.
The shut off valves described here are not suitable for use in
zones 0 and 20 as defined in Directive 99/92/EC. To determine
the qualification and extension of the hazardous zones, see
standard EN 60079-10. If installed and maintained as per the
conditions and instructions given in the enclosed technical
manual, the shut off valve is not a source of specific danger.
In particular, under normal operating conditions, the device
does not emit inflammable substances such as to generate an
explosive atmosphere. The shut off plenum has a work mem-
brane and a safety membrane; if the work membrane breaks,
the safety membrane guarantees gas emission with flow rate
no higher than 30 dm3/h.
A continuous explosive atmosphere able to generate a hazar-
dous zone 0 is emitted solely in the event both membranes
break simultaneously. In the event the valve is installed in an
unmanned or poorly aired location, all the necessary precau-
tions should be taken to prevent the valve from being the cause
of a zone 0. For example, the shut off plenum breather may be
routed outside via a copper pipe connected to the threaded
hole G1/8" by removing the dustproof brass cap.
The assembly position is indifferent; on horizontal piping, do not
position the valve rearming knob facing down. The following
guidelines should be followed: do not lever on the sleeve when
assembling the valve; ensure that the piping is well aligned and
that there are no obstructions or dirt inside; observe the flow
direction as shown by the arrow printed on the valve body;
check that all pressure, voltage, temperature etc. parameters
are complied with; do not install the valve in contact with
plastered walls; do not hinder or in any way obstruct the stroke
The descriptions and photographs contained in this product specification sheet are supplied by way of information only and are not binding. Watts Industries
reserves the right to carry out any technical and design improvements to its products without prior notice. Warranty: All sales and contracts for sale are expressly
conditioned on the buyer's assent to Watts terms and conditions found on its website at www.wattswater.eu. Watts hereby objects to any term, different from or
additional to Watts terms, contained in any buyer communication in any form, unless agreed to in a writing signed by an officer of Watts.
MB-MB/6B-MOI-IT-W-ML-06-20-Rev0
4
of the rearming knob, asclosure may not be guaranteed; fit a
suitable gas upstream of the valve. The shut off valve should be
installed upstream of the pressure regulator. The impulse outlet
(threaded hole G1/8") on the plenum should be connected via
copper pipe, with diameter no less than 4 mm, downstream
of the regulator at a distance from the regulator of 5 times the
diameter of the pipe.
Rearming
These valves are rearmed solely by hand in order to be able
to check and clear the causes of the emergency. To assist the
rearming, all flanged models are equipped with a dual gate pin,
which prevents having to construct by-passes on the piping
between valve upstream and downstream. To rearm the valves
with dual gate pin follow the instructions enclosed inside the
pack, whereas for the threaded series, which has only one gate
pin, simply pull the aluminium knob above the valve sleeve.
Calibration
1.
Check that all the utilities are off.
2.
Slowly open the on/off valve upstream of the system.
3.
Increase the shut off pressure by turning the appropriate
adjusting screw.
4.
Open the valve by following the rearming procedure; if the
valve closes again, increase the shut off pressure again.
5.
Increase the regulator outlet pressure until the set shut
off value. If while increasing the regulator the pressure,
the shut off valve is triggered, increase the shut off
pressure until the valve is rearmed.
6.
Slowly decrease the shut off pressure until the valve
is triggered.
7.
Restore the initial regulator outlet pressure.
8.
Screw on the plastic safety caps on the screws that
adjust the regulator and the shut off valve.
Maintenance
The shut off valves do not require any special maintenance. In
the event of a fault, run a general overhaul and relative test on
site. Periodically check the working efficiency of the entire safety
system by increasing the regulator pressure until the shut off
valve is triggered. If the valve must be disassembled for any
reason, make sure there is no pressure in the circuit.
ALL INSTALLATION, REARMING, CALIBRATION AND
MAINTENANCE OPERATIONS MUST BE CARRIED OUT
SOLELY BY QUALIFIED PERSONNEL.
UK
K0114S – Rev. A 06/2020
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