Cashco SCV-30 - Manual (Page 7)

7 IOM-SCV-30
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 stem movement
stops, is below the upper end of the desired
bench setting, then the com bined stem (3, 6)
length is too long.
a. Rotate jam nuts (17) down to base of
threads on upper coupling (42a).
b. Decrease pressure in the actuator to
approximately mid range of the bench
setting.
c. Rotate upper coupling (42a) CW 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 indicator
washer (16) up against stem (6).
e. Release all pressure from the actuator
and repeat Step 4 previous.
6. If the loading pressure, when stem movement
stops, is above the upper end of the desired
bench setting, then the com bined stem (3, 6)
length is too short.
a. Rotate jam nuts (17) down to base of
threads on upper coupling (42a).
b. Decrease pressure in the actuator to
approximately mid range of the bench
setting.
c. Rotate upper coupling (42a) CCW to
increase the combined stem length. DO
NOT allow actuator stem (6) to rotate in
the actuator.
d. Rotate upper jam nut CW to hold indicator
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) CW 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 in di ca ting washer
(16) 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 (16) as the ref er ence point.
Adjust indicator plate as needed.
10. Slowly decrease air pressure in actuator until
indicating washer (16) is in alignment with the
“O” mark on the indicator plate (23).
11. To limit the up travel at the desired stroke
length, rotate the travel stop nut (52) CW and
secure to bottom of attachment hub (4).
NOTE: Secure the actuator stem (6) by the
fl ats 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 upper pres-
sure level of bench setting, the valve plug (3)
will be in the "C" position. At the lower level
of the bench setting, the actuator pressure
should be within ±8% of the lower bench
range for the designed stroke length.
12. Release all pressure from actuator.