Cashco 964 - Manual (Page 4)

IOM-964 4
5. For ATO-FC Reverse Action Units:
a. (Note PA.)
b. Step A. Rotate valve stem (3) CW (viewed
from above) to disengage the ac tu a tor
stem (19) from the valve stem (3), while
holding the actuator stem (19). Record
the num ber of valve stem rev o lu tions for
Step A above. When the dis en gage ment
reach es about 50% of full stroke trav el,
(Note RP). Step A is com plet ed.
c. Step B. Support the actuator as sem bly
(AA) from above. Fully loosen yoke
nut (17) and remove. Lift the actuator
as sem bly (AA) up wards ap prox i mate ly
1/4"-3/8" (6-8 mm). Again, rotate valve
stem (3) CW (viewed from above) to dis-
en gage the ac tu a tor stem (19) from the
valve stem (3) while holding the ac tu a tor
stem (19). Record the number of valve
stem (3) rev o lu tions for Step B above.
This should allow the ac tu a tor stem (19)
to fully dis en gage from the valve stem (3).
NOTE: Take notice of the parts “dan gling
loosely” about the stem (3), the order of their
lo ca tion and their proper orientation.
d. Fully raise the actuator assembly (AA)
from the valve body assembly (BA). Re-
move cautiously to prevent the dan gling
parts - position indicating disc (20), ac-
ces so ry plate ((AP)), yoke nut (17) - from
fall ing.
6. For ATC-FO Direct Action Units:
a. Step A. Rotate valve stem (3) CW (viewed
from above) to disengage the ac tu a tor
stem (19). Do not rotate the stem (3)
into the seat (11). Record the number
of valve stem (3) rev o lu tions for Step A
above. When the dis en gage ment reach es
about 75% of full stroke travel, Step A. is
com plet ed.
b. Step B. Support the actuator as sem bly
(AA) from above. Fully loosen yoke nut
(17) and remove. Lift the actuator as-
sem bly (AA) upwards ap prox i mate ly 1/4" -
3/8" (6-8 mm). Again, rotate valve stem
(3) CW (viewed from above) to dis en gage
the ac tu a tor stem (19) from the valve stem
(3), while holding the actuator stem (19).
Record the number of valve stem rev o lu-
tions for Step B. This should allow the
stem (19) (3) to fully disengage.
NOTE: Take notice of the parts “dangling
loosely” about the stem (3), the order of their
lo ca tion and their proper orientation.
c. Fully raise the actuator assembly (AA)
from the valve body assembly (BA). Re-
move cau tious ly to prevent the dan gling
parts – po si tion indicating disc (20), ac-
ces so ry plate ((AP)), yoke nut (17) - from
falling.
C. Actuator Replacement:
1. Secure body assembly (BA) in a vise with the
valve stem (3) oriented ver ti cal ly. Push plug/
stem (3) down until the plug (3) touches the
body (1) for ATO-FC actions, or seat ring (11)
for ATC-FO ac tion.
2. Secure the actuator assembly (AA) from above.
3. This procedure assumes that the bonnet (2)
has been bolted to the body (1), with stem
jam nuts (18) on the valve stem (3).
4. Lower actuator assembly (AA) until the valve
stem (3) penetrates the opening in the yoke
(1). Re po si tion the “dangling parts” - yoke
nut (17), ac ces so ry plate ((AP)) and in di cat ing
disc (20) - over the body stem (3). Con tin ue
to lower the actuator assembly (AA) until there
is ap prox i mate ly 1/4" (6 mm) space between
stems (19) (3).
5. Connect a temporary air supply hose that has
an ad just able airset with gauge to the ac tu a tor
inlet to allow pres sur iza tion.
6. Slowly pressurize actuator to bring the ac tu a tor
stem (19) to with in 1/8" (3 mm) of reaching
the valve stem (3).
7. Hand lift valve stem (3) up to touch ac tu a-
tor stem (19). Rotate valve stem (3) CCW
(viewed from above) to en gage with ac tu a tor
stem (19). Use the total number of revs en-
gage ment recorded in Step IV.B. as the guide
to control engagement of the stems (19) (3).
While en gag ing, rotate yoke nut (17) as able
No. of revolutions to disengage valve stem
from actuator stem:
Step A
___________ Step B __________
TOTAL _________