9
IOM-987
(16) to the "C" mark on the indicator plate
(23), making sure to use the “top edge” of
the indicating washer (16) as the reference
point. Adjust indicator plate as needed.
10. Increase pressure in the actuator until the
indicating washer (16) is in alignment with
the "O" mark on the indicator plate.
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 flats when rotating the travel stop nut.
NOTE: “Stroke” length is indicated on the
nameplate (40), and is the distance between
the “C” and “O” marks of the indicator plate
(23).
NOTE: The proper calibration of the actuator/
valve unit will occur when at the lower
pressure level of bench setting, the valve
plug (4) will just begin to travel from the "C"
position. At the upper level of the bench set,
the actuator pressure should be within ± 8%
of the upper bench setting for the designed
stroke length.
12. Release all pressure from actuator.
C. Procedure - Direct Action, ATC-FO:
1. Reference the nameplate (40) attached to
the actuator yoke (3). Determine the bench
setting of the installed range springs (10) from
the nameplate (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
adjustable airset regulator and gauge to the
upper actuator connection. 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 (4) makes
contact with the seat and travel stops, touch
the stem above the packing studs with one
finger. (Stem movement will stop when the
plug engages the seat.)
4. Slowly pressurize the actuator to a pressure
equal to the upper pressure level 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 stops.
5. If the loading pressure, when the stem
movement stops, is below the upper end of
the desired bench setting, then the combined
stem (4, 6) length is too long.
a. Rotate both jam nuts (17) down to base of
threads on stem (4) and tighten together.
b. Decrease pressure in actuator to
approximately mid range of the bench
setting.
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 CW to hold indicating
washer (16) up against stem (6).
e. Release all pressure from the actuator
and repeat Step 4 previous.
6. If the loading pressure when the stem
movement stops is above the upper
end of the desired bench setting, then
the combined stem (4, 6) length is too
short.
a. Rotate both jam nuts (17) down to
base of threads on stem (4) and tighten
together.
b. Decrease 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
indicating washer (16) up against stem
(6).
e. Release all pressure from the actuator
and repeat Step 4 previous.
7. After the closed set point pressure has been
established, rotate lower jam nut (17) CCW
up tight under the upper jam nut.
8. Increase pressure in the actuator to the upper
pressure level of the bench setting.
9. Observe the location of the indicating washer
(16) to the "C" mark on the indicator plate
(23), making sure to use the “top edge” of
the indicating washer (16) as the reference
point. Adjust indicator plate as needed.
10. Decrease pressure in the actuator until the
indicating washer (16) is in alignment with the
"O" mark on the indicator plate.
11. To limit the up travel at the desired stroke
length, rotate travel stop nut (52) CW and
secure to bottom of attachment hub (4).
