Cashco 964 - Manual (Page 8)

IOM-964 8
35. Tighten packing nuts (15) evenly in ½ revolu-
tion increments, until the packing fl ange (4)
is resting evenly on the upper edge of the
bonnet (2) at the packing box. Snug both
nuts (15) tightly.
36. Raise actuator assembly (AA). (Note RP.)
Lower into body (1) over bonnet studs/bolts
(16). Align with match marks.
37. For ATO-FC action units, wiggle the ac tu a tor
as sem bly (AA) to assist in align ment.
38. For ATC-FO action units, pres sur ize ac tu a tor
to the “high er” number of the bench set range
in di cat ed on nameplate (12) plus 2 psig (.14
Barg); for 5-15 psig (.34-1.03 Barg) bench
setting, pres sur ize to 17 psig (1.17 Barg).
VI. CALIBRATION
A. General:
1. This section only covers cal i bra tion of the
control valve with Actuator Models C27/C53.
2. Positioner, if in stalled, requires ref er ence to
the spe cifi c positioner mod el IOM for prop er
cal i bra tion pro ce dure.
3. All indicated items numbers that are with re-
spect to IOM-C27-C53 will be in pa ren the sis
and un der scored; i.e. (20); those that reference
the po si tion er IOM will be in double paranthe-
sis; i.e. ((AP)). All item numbers that are with
respect to this IOM-964 are not un der scored;
i.e. (3).
B. Procedure - Reverse Action, ATO-FC:
1. Reference the name plate (40) at tached to
the ac tu a tor yoke (3). De ter mine the bench
set ting of the in stalled range springs (10) from
the name plate (40); i.e. 5-15 psig (.34 -1.0
Barg), or 15-60 psig (1-4.1 Barg).
2. Connect a temporary air supply with an in-line
ad just able airset regulator and gauge to the
lower actuator con nec tion. See Section IV. A.
6. for appropriate supply pressure. DO NOT
LOAD with any air pressure at this point.
3. To determine when stem/plug (3) begins to
lift out of the seat, touch the stem above the
packing studs with one fi nger. (Stem will begin
This should “lift” the bonnet (2) and “seat”
the plug (3) fi rmly into the seat ring (11) for
align ment pur pos es. Wiggle the ac tu a tor
as sem bly (AA) to assist in align ment.
39. Wrench-tighten the bonnet bolt ing (16) (17) in
an al ter nat ing cross-pat tern in 1/4 rev o lu tion
in cre ments. Torque bonnet bolt ing to 30-35
ft/lbs (40-47 N-M) for sizes 1/2" - 1-1/2" , and
50-55 ft/lbs (66-73 N-M) for size 2"
40. For ATC-FO action units, release ac tu a tor
pres sure.
41. Hammer rap yoke nut (29) tight.
42. Calibrate unit per Section VI.
to move when actuator pressure exceeds
the spring load.)
4. Slowly pressurize the ac tu a tor to a pres sure
equal to the lower pres sure lev el of the bench
setting; i.e. for a 5-15 psig (.34 -1.0 Barg)
range, set pressure at 5 psig (.34 Barg). Take
note of pressure reading when the stem fi rst
begins to move.
5. If the loading pressure for the start of stem
movement is below the lower end of the
desired bench setting, then the com bined
stem (3, 6) length is too short.
a. Rotate both jam nuts (18) down to base of
threads on stem (3) and tighten together.
b. Increase pressure in the actuator to
approximately mid range of the bench
setting.
c. Rotate upper jam nut CW to increase
the combined stem length. DO NOT
allow actuator stem (6) to rotate in the
actuator.
d. Rotate upper jam nut CCW to hold indi-
cating washer (26) up against stem (6).
e. Release all pressure from the actuator
and repeat Step 4 previous.
6. If the loading pressure for the start of stem
movement is above the lower end of the
desired bench setting, then the com bined
stem (3, 6) length is too long.
a. Rotate both jam nuts (18) down to base of
threads on stem (3) and tighten together.
SECTION VI