IOM-48
5
V. MAINTENANCE
A. General:
1. Hereafter, all maintenance, disassembly, etc.,
is as sumed to be done in an indoor shop.
2. Most actuators are a sub-assembly that is
unitized with a body sub-assembly. Ref er ence
should be made to the IOM for the correct
body utilized.
3. Where the body is not being disassembled,
special care MUST be exhibited to prevent
valve stem rotation during any disassembly
or reassembly for all types of valves. Follow-
ing this procedure will ensure not damaging
seat ing surfaces.
4. Remove all instrument tubing and in ter con -
nect ed electrical wiring. Label “ends” to en sure
proper reconnection.
5. All indicated Item Numbers that are with re-
spect to IOM-Ranger, IOM-Premier EZO or
IOM-Premier Unlined will be in parenthesis
and underscored; i.e. (20); the same is true
for Model 73N-B P/P positioner parts.
6. All Item Numbers that are with respect to this
IOM-48 are not underscored; i.e. (19).
7. Item Numbers that relate to the Model 9540
or Smart positioners ((PA)) are in a double
set of pa ren the sis and are underscored; i.e.
((3)).
B. Separation of Body Assembly (BA) from Ac-
tu a tor Assembly (AA):
1. Place completely joined valve assembly (AA)
(BA) upon a
fl
at work surface with suf
fi
cient
room to move the individual sub-as sem blies
(AA) (BA) around. Place matchmarks on valve
yoke (12), arm housing (4) and ac tu a tor lower
casing (2) to use as ref er enc es.
2. Remove cover plate (20) away from arm
hous ing (4) by removing four machine screws
(36).
3A. Units with Model 73N-B P/P Positioner or No
Positioner, and No Travel Limit Switch:
a. Using a 3/16" allen key wrench, remove
the three cap screws (31) securing the
dial lens (14), travel indicator dial (15)
and coverplate (13).
b. Remove cap screw (32) and lock tooth
washer (55) se cur ing the bright or ange-
col ored travel in di ca tor (16) to the upper
end of valve stem (Rang er (7)), (Premier
(3.2)) using a 7/32" allen key wrench. Re-
move travel in di ca tor (16) off of pro trud ing
lo ca tor pin (51).
c. If equipped with a Model 73N-B P/P po-
sitioner, re move the four cap screws (33)
that secure the positioner assembly (PA)
to the arm housing (4) using a 3/16" allen
key wrench. Remove positioner as sem bly
(PA) and feed back range spring (102).
Loop a 6" piece of
fi
ne wire around the
feedback linkage subassembly (72). Place
one screw (33) back into a tapped open ing.
Pull wire taut and wrap around pro trud ing
screw (33) to keep the linkage (72) from
interfering with further dis as sem bly.
3B. Units with End-of-Shaft Model 9540R Posi-
tioners:
a. Remove clear indicator cover ((22)) by
removing two cap screws ((A3)).
b. Remove red plastic pointer ((34)) by pull-
ing outwards from hub of post-end screw
((23)).
c. Make a matchmark on the char ac ter iza-
tion cam ((24)) at the point where the cam
follower ((31)) touches. Using a wrench
remove post-end screw ((23)) that se cures
characterization cam ((24)). Pull feedback
lever ((13)) downwards; re move cam
((24)) and adhered to lock toothed washer
((28)) and shouldered wash er ((27)).
d. Remove the positioner unit ((I/P)) ((P/P))
from the baseplate ((26)) by removing cap
screws ((11)) with lock washers ((12)) from
side and back of baseplate ((26)).
e. Remove the four cap screws ((78)) se cur-
ing the bracket ((76)), baseplate ((26))
assembly and coverplate (13) to the arm
housing (4).
3C. Units with End-of-Shaft Model 991 or PS2 I/P
Positioners:
a. Remove cap screws (31) securing the
positioner mounting bracket ((9)) to coverplate
(13).
b. Set positioner/bracket assembly to the
side.
c. Remove set screw ((16)), washer ((17))
from end of valve stem (Ranger (7)), (Premier
(3.2)) securing carrier linkage ((3)) to stem.
d. Remove linkage ((3)) from end of stem.
SECTION V