10-2
WARNING: Keep hands, hair, clothing, etc.
away from the rotating disc and the seat when
operating the valve. Failure to do so could
cause serious injury.
CAUTION: Because of Valdisk’s self-centering
seat, there is no reason to open the valve at any
time during installation. Therefore, the valve
should remain closed until the valve is fully
installed.
4. Connect air supply and instrument signal. Throt-
tling valves are usually equipped with valve
positioners. Two connections are marked for the air
supply and for the instrument signal. Both cylinder
and positioner are suitable for 150 psi air supply. An
air regulator is not required unless the supply
pressure exceeds 150 psi. An air filter is recom-
mended unless the supply air is unusually clean
and dry. All connections must be free of leaks.
CAUTION: On valves equipped with air filters,
the air filter bowl must point down; otherwise,
the air filter will not perform properly.
NOTE: In some rare cases, the air supply must be
limited to 100 psi rather than 150 psi. In this case,
a sticker found near the upper air port on the
cylinder will indicate this and an air regulator should
be installed to insure the supply pressure does not
exceed 100 psi.
5. Make sure proper clearance exists internally in the
mating piping to permit proper disc rotation.
6. Apply recommended torque values to line flange
bolting for proper sealing (see Table I).
Quick-check
Prior to start-up, check the control valve by following
these steps:
1. Check for full stroke by making the appropriate in-
strument signal change. Observe disc position
indicator plate mounted on the transfer case. The
disc should change position in a smooth, rotary
fashion.
2. Check all air connections for leaks. Tighten or
replace any leaky lines.
3. Evenly tighten the packing nuts to slightly over
finger-tight.
CAUTION: Do not overtighten packing. This
can cause excessive packing wear and high
shaft friction, which may impede shaft rotation.
After the valve has been in operation for a short
time, check the packing nuts to make sure they are
just over finger-tight (readjust if necessary). If
packing box leaking occurs, tighten the packing
nuts only enough to stop leakage.
4. To observe the valve failure mode in case of air
failure, position the valve to mid-stroke and shut off
Table I: Flange Bolting Torques
Valve
Rating
Torque
Size (inches)
(ft./lbs.)
150
118
2
300
118
600
118
150
118
3
300
209
600
209
150
118
4
300
209
600
337
150
209
6
300
209
600
505
150
209
8
300
337
600
728
10
150
337
300
505
12
150
337
300
728
14
150
505
16
150
505
18
150
728
20
150
728
24
150
1009
30
150
1009
Installation
1. Before installing the valve, clean the line of dirt,
scale, welding chips, and other foreign material.
Clean the gasket surfaces thoroughly to insure
leak-proof joints.
2. Check flow direction to be sure valve is installed
correctly. Fail-closed valves should be installed
with the shaft upstream only on gas service. It
is preferred that liquid service valves must be
installed with the shaft downstream regardless of
air failure action. However, under certain flow
conditions the valve can flow shaft upstream. Con-
sult factory if the valve must be mounted with the
shaft upstream in liquid service. Fail-open valves
should be installed with the shaft downstream.
WARNING: When installing the valve in-line
between flanges, make certain the flange face
gasket covers both seat retainer and body and
surface. Failure to do so will cause excessive
leakage downstream. Refer to “Seat Insert/Snap-
ring Configuration” in Figure 1.
3. Fully close the valve before and during the installa-
tion process.
