Fisher 92S Instruction Manual page 9

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TYPE 6492Hm SAFETY
OVeRRIDe PILOT
E0663
NPS 2-1/2, 3, AND 4 / DN 65, 80, AND 100 BODy SIzeS SAFeTy OVeRRIDe PIPING SCHeMATICS
1. Only personnel qualified through training and
experience should install, operate, and maintain
a Type 92S regulator. Before installation, make
sure that there is no damage to, or debris in the
regulator. Also make sure that all tubing and
piping are clean and unobstructed.
2. A Type 92S regulator may be installed in any
orientation, as long as flow through the regulator
matches the direction of the arrow on the main
valve body. However, the regulator should not be
installed in a tall, vertical pipeline where condensate
could collect and create a pressure head affecting
regulator performance.
3. Apply steam-compatible pipe compound to
the external pipeline threads for a threaded
body, or use suitable line gaskets for a flanged
body. Use acceptable piping procedures when
installing regulator.
4. If continuous operation of the system is required
during inspection and maintenance, install a
three-valve bypass around the regulator. If the
flowing medium contains solids, install a properly
sized strainer upstream of the regulator.
Note
A clogged vent on the spring case of
a standard Type 6492H or 6492L pilot
may cause the regulator to function
improperly. install and maintain a
regulator with a standard pilot so that
the spring case vent stays clear.
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TYPE 92S mAiN VALVE
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TYPE 6492H PiLOT
Figure 3. Typical Installations (continued)
5. As shown in Figure 3, connect a control line as
large as possible but no smaller than 3/8-inch /
9.5 mm diameter bushed down to the 1/4 NPT
connection in the cylinder spacer NPS 1, 1-1/2,
or 2 / DN 25, 40, or 50 body size or the pilot body
NPS 2-1/2, 3, 4, or 6 x 4 / DN 65, 80, 100, or 150 x
100 body size.
6. Locate the control line connection at least
10 pipe diameters away from the regulator or
swage and in a section of straight pipe.
7. Do not locate the control line connection in a gate,
plug, or check valve, in an elbow, swage, or other
area of the pipeline where turbulence or abnormal
velocities may occur, or in a large-volume vessel
that can cause noticeable control lag.
8. Slope the control line away from the pilot to let
condensate drain into the pipeline.
9. Install a shutoff valve (not a needle valve) in the
control line to isolate the pilot during maintenance.
10. Install a pressure gauge in the control line, or near
the regulator, to aid in setting the outlet pressure.
11. With a pressure-loaded or on-off pilot, connect the
pressure-loading or on-off piping or tubing to the
1/4 NPT connection in the tapped pilot spring case.
12. The pressure setting of the regulator is
determined by:
TYPE 6492H PiLOT
• The pilot control spring adjustment on a
standard pilot, or
Type 92S
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