IOM-POSR-2
8
cham ber (2) to ensure the concentricity of the
recess in the spring button (16) with the top
opening. It may be necessary to use an awl
or similar tool to realign the spring button (16)
as much as possible. The spring chamber (2)
is not tightened down, and may be temporarily
“shifted” to help ensure alignment for the
adjusting screw (19) en gage ment.
42. Place lubricant onto the upper exposed
threads of the spring chamber’s (2) adjusting
screw (19) opening. Place lubricant onto
the ad just ing screw (19) lower-end threads.
Engage adjusting screw (19) back into spring
cham ber (2) by rotating CW (viewed from
above). Engage only until resistance is made
with the range spring (15) via the spring button
(16).
43. Realign the spring chamber (2) flange with the
body (1) flange, and wrench-tighten bolting
(17, 18) in an al ter nat ing, crossing pattern.
Final tightening should be done with a torque
wrench to 15 ft.-lbs. (20 N-M).
44. Continue CW rotation (viewed from above) of
ad just ing screw (19) until locknut (20) touches
spring chamber (2). Back adjusting screw (19)
out by rotating CCW (viewed from above) two
revolutions. This position will ap prox i mate the
pressure setpoint prior to dis as sem bly if the
locknut (20) is only loosened two revolutions as
directed in article 2. previous, this subsection.
45. Reconnect pilot valve (PV) to main valve (MV).
See Figures 6, 7 and 8 for correct orientation.
Pressure leak test the complete assembly per
Section VII.D.
D. Main Valve (MV):
1. General Note: The actuator/topworks section
of the main valve (MV) is sufficiently “heavy”
for the 3" and 4" (DN80 and 100) body sizes
that the procedures following are written
to include overhead hoisting. Additionally,
fol low ing the procedure will ensure that the
internals subassembly (IS) will not “fall from
within the cylinder (3)” when the cylinder (3)
is oriented vertically, when gravity overcomes
seal (12) friction.
WARNING
Never replace bolting (17, 18) with just any bolting if
lost. Bolt heads and nuts are marked with spec i fi ca tion
identification markings. Use only proper grades as
replacements.
For the 1" through 2" main valve (MV) body
sizes, the actuator/topworks is not so heavy
that an overhead hoist is re quired. However,
if an overhead hoist is not used, im prop er
handling of the removed cylinder (3) and
internals subassembly (IS) can still result in
the internals sub as sem bly (IS) “falling from
within the cyl in der (3)” by gravity, so the above
“warning statement” is still valid.
2. Using an overhead hoist, rig the main valve
(MV). Lift and securely place the main body
(1) in a vise with the cylinder head (4) directed
upwards.
3. Draw or embed a match mark between the
cyl in der head (4), cylinder (3), bonnet (2) and
body (1).
4. Loosen elongated cylinder bolting (16, 17) by
rotating each nut (17) CW (viewed from above)
until fully removed. Withdraw each of the four
elongated bolts (16).
NOTE:
Sizes 3" and 4"
(DN80 and 100) have the body’s (1) bonnet
flange drilled and tapped so that no bottom
nut (17) is required.
5. While holding the cylinder (3) by hand, use
a wooden block to lightly rap the underneath
side of the cylinder head (4) to release the
head-to-cylinder joint. Once loosened, re move
the cylinder head (4).
6. Place locking pliers on stem nut (15). Keep
the pliers within the cylinder’s (3) interior away
from the cylinder (3) wall.
7. While placing downward force on the locking
pliers of the previous article, grasp the cyl in der
(3) by hand and simultaneously lift up wards
and wiggle sideways at the top until the joints
at the lower end of the cylinder (3), bonnet (2)
and body (1) loosen. If necessary, use a flat,
sharp-edged tool to get under the bonnet (2)
at the joint between the bonnet (2) and the
body (1) while gently pushing the cylinder’s
(8) upper edge sideways back-and-forth; do
not apply excessive sideways force to the
WARNING
Follow procedures given herein in handling main valve
topworks! Failure to heed may result in internals sliding
out of cylinder and falling down wards to im pact on foot!
