XLC 420
7
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The set up and valve regulation has to be carried out by qualified personnel only, or
directly from CSA service. Improper actions can lead to permanent damages to the
valve, its internal components and system equipments along with possible injuries of
the people involved.
The difference in pressure generated by the valve during the pressure
sustaining/relief function will produce a thrust proportional to the pressure itself.
Anchorage blocks and way of preventing valve’s movement or shifting need to be
taken into account.
Set up
For the proper set up of XLC 400 Mod. 420 reader is advised to use the following points (rif. picture
1 on page 4).
Make sure the isolation ball valves of the circuitry (2-3-4) are fully open
The valve is at first isolated from the main line as both sectioning devices, upstream and
downstream, are closed.
Unless a specific setting has been required in the order remove the hood from the pilot (6)
and turn clockwise the screw to increase the spring force in the cover almost completely.
The upstream set pressure depends on the pilot setting and it is proportional to the charge
of the spring. Regulation chart are available on request. Doing so the valve will be brought
to the closed position as the upstream set point would become higher than the incoming
pressure.
Slowly operate on the upstream gate valve to open it by 30 %, leaving the downstream
sectioning device completely closed.
Pressure will enter
the valve’s body, circuitry and bonnet pushing down the diaphragm and
mobile block against the obtu
rator and inducing the valve’s closure
Remove the air entrapped in the bonnet, during the operation, by means of the air release
device located on top of the position indicator (7) leaving it flowing for at least 20 seconds.
Open completely the upstream gate valve
Slowly open the downstream gate valve, to a maximum of 40% of the stroke, act on the
spring on the pilot decompressing it to generate some flow through the valve and allow for
some time to react, this depends on how big is the system downstream and on the
variations in demands.
Having generated the flow it means that the upstream pressure set point has reached the
incoming pressure value.
