Cashco 988-MB - Manual (Page 14)

14 IOM-988/989-BODY
11. To limit the up travel at the desired stroke
length, rotate the travel stop nut (52) CW and
secure to bottom of the attachment hub (4).
NOTE: Secure the actuator stem (6) by the
fl ats when rotating the travel stop nut.
NOTE: “Stroke” length is in di cat ed on the
name plate (40), and is the dis tance be tween
the “C” and “O” marks of the indicator plate
(23).
NOTE: The proper calibration of the ac tu a tor/
valve unit will occur when at the lower pres-
sure level of bench setting, the valve plug (3)
will just begin to travel from the "C" po si tion.
At the upper level of the bench setting, the
actuator pressure should be within ± 8% of the
upper bench setting for the designed stroke
length.
12. Release all pres sure from actuator.
C. Procedure - Direct Action, ATC-FO:
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; 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
upper 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) makes
contact with the seat and travel stops, touch
the stem above the packing studs with one
fi nger. (Stem movement will stop when the
plug engages the seat.)
4. Slowly pressurize the ac tu a tor to a pres sure
equal to the upper pres sure lev el of the bench
setting; i.e. for a 5-15 psig (.34 -1.0 Barg)
range, set pressure at 15 psig (1.0 Barg). Take
note of the pressure reading when stem travel
actually stops.
5. If the loading pressure, when the stem move-
ment stops, is below the upper end of the
desired bench setting, then the com bined
stem (3, 6) length is too long.
a. Rotate both jam nuts (52) down to base of
threads on stem (3) and tighten together.
b. Decrease pressure in the actuator to
approximately mid range of the bench
setting.
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 (52) down to base of
threads on stem (3) and tighten together.
b. Increase pressure in the actuator to ap-
proximately mid range of the bench set-
ting.
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 indicat-
ing washer (51) 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 (52) down to base of
threads on stem (3) and tighten together.
b. Increase pressure in the actuator to ap-
proximately mid range of the bench set-
ting.
c. Rotate lower jam nut CCW to shorten the
combined stem length. DO NOT allow
actuator stem (6) to rotate in the actuator.
d. Rotate upper jam nut CCW to hold indicat-
ing washer (51) up against stem (6).
e. Release all pressure from the actuator
and repeat Step 4 previous.
7. After the opening set point pressure has been
established, rotate lower jam nut (51) CCW
up tight under the upper jam nut.
8. Release all pressure from the actuator.
9. Examine the location of the in di ca ting washer
(51) to the "C" mark on the in di ca tor plate
(23), mak ing sure to use the “top edge” of
the in di ca ting washer as the ref er ence point.
Adjust indicator plate as needed.
10. Increase pressure in the actuator until the
indicating washer (51) is in alignment with the
"O" mark on the indicator plate.