7
ANDERSON GREENWOOD SERIES 400 PISTON PILOT POPRV
InstallatIon and MaIntenance InstructIons
3 PILOT MAINTENANCE
Refer to Figures 3, 4, and 5.
Arrange all parts in an orderly sequence on
a flat work surface during disassembly. This
will facilitate assembly and help ensure that
the correct parts are assembled in the proper
sequence.
3.1 Disassembly
Before beginning disassembly, bleed off any
pressure trapped in the main valve or pilot.
3.1.1 Standard pilot – gas or liquid service
NOTE
If the pilot is equipped with a lift lever, the lift lever
handle assembly (Item 42) must be removed from the
cap (Item 17) before continuing with disassembly. To
do this, hold the lift lever handle in the position shown
in Figure 3, unscrew the handle assembly bushing
(Item 43) from the cap, and remove the handle
assembly.
Remove the cap (Item 17), for pilot with lift
lever remove jam nut (Item 44) and lift lever
nut (Item45), loosen the jam nut (Item 16),
and turn the adjustment screw (Item 15)
counterclockwise to relieve the spring tension.
Exercise caution when removing the spring
bonnet (Item 14) from pilots set above 500 psig,
as spring tension is not completely relieved
until the bonnet is removed. Remove the spring
bonnet, spring (Item 6), and spring washers
(Item 13).
Lift the piston plate (Item 4) with internal parts
attached upward and remove from the body
(Item 1). Unscrew the piston nut (Item 9) from
the feedback piston (Item 3) and remove the
lock washer (Item 36). Disassemble the sense
piston (Item 10) and feedback piston from the
piston plate. Unscrew the inlet nozzle (Item 5)
from the feedback piston. Remove the spool
spring (Item 8) and inlet nozzle with the spool
from the feedback piston.
Remove the bias spring (Item 11) and body
plug (Item 2) from the body. Using a hex key
(Allen wrench) inserted through the bottom
of the body into the hex socket in the outlet
nozzle (Item 25), unscrew the outlet nozzle and
remove it through the top of the body. Note
that when viewed from the bottom of the body,
the hex key is turned clockwise to unscrew the
outlet nozzle.
3.1.2 Iso-Dome pilot – gas service
NOTE
All Iso-Dome pilots are gas service pilots; however,
fully assembled valves with these pilots may be either
gas service valves or liquid services valves.
After bleeding off any pressure trapped in the
main valve or pilot, remove the pilot with the
regulator (Item 55) attached from the main
valve. Unscrew and remove bracket bolts
(Items 52) and bracket bolts (Items 53). Slide
the bracket (Item 49) outward approximately
1½” along the regulator cover spacer (Item 50).
Using an
11
/
16” wrench, unscrew the adapter
(Item 48) with regulator attached from the body
(Item 1). If necessary, slide the bracket farther
out along the cover spacer so that it does not
hit the body. Support the regulator during
this operation in order to avoid damaging the
adapter threads or the body threads. Loosen
set screw (Item 54) and remove regulator cover
cap (Item 51), regulator cover spaces (Item 50),
and bracket.
Continue pilot disassembly in accordance with
the procedures described in paragraph 3.1.1
except that the Iso-Dome pilot uses an adapter
in place of the body plug (Item 2) in a standard
pilot.
3.1.3 Iso-Sense pilot – gas or liquid service
The Iso-Sense pilot sectional drawing shown in
Figure 3 is presented for identification purposes
only. This is a special pilot assembly which may
incorporate non-standard components. Contact
Anderson Greenwood for replacement parts
and maintenance instructions for individual
pilots (serial number is required for complete
identification).
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