XLC 420
18
Reassembly
To reassemble do the reverse of the disassembly procedure positioning the main shaft back into
the grip along with all the pieces. It is very important not to forget the O-Ring (21) and to
set the
nut tight
(10) to assure a proper torque between the diaphragm and the plane gasket. Please be
extremely careful with this step because a nut not properly tight may engender movements making
the mobile block unstable,
therefore affecting the valve’s performance.
Put the mobile group back into the valve’s body placing the shaft into the sealing seat guide, make
the holes of the diaphragm match the studs and position the spring (9) under the cover.
Set the nuts tight using a cross over pattern, then put the circuitry back to its original position.
Final inspection
Make sure that the internal mobile block can move without any friction, this can be verified simply
by gradually putting the main chamber under pressure and checking the movement of the
indication rod, as explained before.
Examine the status of the plane gasket simply by checking the perfect water tightness of the
sealing seat. At this point proceed by opening the upstream gate valve full throttle to have the
normal working conditions, check for any leakage through the cover or the nuts, should that
happen set them tighter.
