Startup With Existing Regulator Installation After Normal Shutdown; Shutdown; Maintenance; Types 6492L, 6492H, 6492Ht, 6492Hm, And 6492Htm Pilots - Fisher 92S Instruction Manual

Startup with Existing Regulator
installation After Normal Shutdown
1. Open the upstream and downstream block valves
and let the regulator take over control at the
existing pilot control spring setting.
2. If a bypass line is used, slowly control the bypass
line block valve.

Shutdown

1. If a bypass line is used, slowly open the
bypass line block valve while monitoring the
downstream pressure.
2. Close the control line shutoff valve.
3. Close the downstream block valve.
4. Close the upstream block valve.
5. If a pressure-loaded or on-off pilot is used, close
the needle valve to the pilot.
6. Vent the regulator and control line to release any
trapped pressure.

maintenance

Regulator parts are subject to normal wear and
must be inspected periodically and replaced
as necessary. The frequency of inspection
and replacement depends upon the severity of
service conditions and upon applicable codes and
government regulations.
!
To avoid personal injury resulting
from sudden release of pressure,
isolate the regulator from all pressure
and cautiously release trapped
pressure from the regulator before
attempting disassembly.
Types 6492L, 6492H, 6492HT, 6492Hm,
and 6492HTm Pilots
These procedures are to be performed if inspecting,
cleaning, or replacing any pilot parts, or if cycling,
erratic control, or too high or too low an outlet
(control) pressure is noted. Perform only those
procedures in this section required to correct the
problem. Refer to Figure 4 for key numbers unless
otherwise noted.
WARNiNg
Note
Before performing any maintenance,
loosen the hex nut (key 16), if used,
and turn the adjusting screw (key 15) or
handwheel (key 38) counterclockwise
until all compression is removed from
the control spring (key 12). Remove
the pilot from the pipe nipple and
connectors (keys 82 and 83, Figure 6).
1. Unscrew the valve guide (key 2). Remove the
screen (key 77), inner valve (key 4), valve spring
(key 3), and stem (key 7). Unscrew the seat ring
(key 5). Examine the seat ring and plug seating
surfaces for damage.
2. Clean and replace parts as necessary. Apply
sealant to the seat ring threads. Thread the seat
ring into place and tighten it to between 19 and
25 foot•pounds / 26 and 34 N•m of torque.
3. Handle the parts carefully, and place the valve
spring (key 3) in the valve guide (key 2). Slide the
inner valve (key 4) over the spring and into the
valve guide. Place the screen (key 77) onto the
valve guide. Place the stem (key 7) in the center
hole of the valve guide. Apply sealant to the valve
guide threads, and screw the guide plus attached
parts into the body (key 1).
4. Remove the pipe plug (key 74). Then remove
the bleed restriction (key 76) on Types 6492L,
6492H, and 6492HT or the pipe plug (key 94) on
Types 6492HM and 6492HTM. Clean and replace
the bleed restriction or pipe plug as necessary.
5. Apply sealant to the threads of the bleed restriction
(key 76) or pipe plug (key 94) and install.
6. Apply sealant to the threads of the pipe plug
(key 74). Thread the pipe plug into place and tighten
using 5 to 15 foot•pounds / 7 to 20 N•m of torque.
7. Remove the cap screws (key 17), spring case
(key 14), control spring (key 12), and upper spring
seat (key 13) from the body.
8. Remove the lower spring seat (key 11, Types 6492H
and 6492HT pilots only) or diaphragm plate
assembly (key 24, Type 6492L pilot only),
diaphragms (key 10), and diaphragm gasket
(key 18) from the body. Inspect and clean the
diaphragm gasket, and replace if necessary.
9. Unscrew the bellows retainer (key 8) and remove
the bellows (key 9). Replace worn parts as
necessary, and install the bellows and bellows
retainer. Tighten the bellows retainer to between
19 and 25 foot•pounds / 26 and 34 N•m.
Type 92S
11