Installing The Stem Connector Assembly - Fisher 667 Instruction Manual

from the valve. Mark the end of the actuator stem on a
nearby surface using tape or some other method.
6. Slowly decrease the diaphragm pressure until the
lower bench set loading pressure is applied. Again, the
down-stops should be against the yoke.
7. Measure the distance between the mark or tape to
the end of the actuator stem. This distance should
match the travel span shown on the travel indicator
scale (key 32).
8. If the span of travel is correct, bench set is com-
plete. Proceed to the Installing the Stem Connector
Assembly subsection.
9. If the travel span is not exact, remember the free-
length and load rate tolerances for the spring may pro-
duce a slightly different span than specified. Contact
your Fisher Controls sales office or sales representa-
tive for assistance.

Installing the Stem Connector Assembly

When installing the stem connector assembly (key 31),
the actuator and valve stem threads should engage
the threads of the stem connector by a distance equal
to the diameter of the stem.
Replacement stem connectors are an
assembly of two stem connector halves,
cap screws, and a spacer between the
connector halves. Remove the spacer
and discard it, if present, before clamp-
ing the actuator and valve stems togeth-
er.
1. If necessary, push the valve stem down so that the
valve plug is touching the seat ring on direct-acting
valves. For reverse-acting valves, pull the stem up to
the closed position. Always start with the valve plug on
the seat.
2. If necessary, screw the valve stem locknuts down,
away from the connector location. For all actuators
except size 87, ensure that the travel indicator disk
(key 34) is on top of the locknuts.
3. Apply the diaphragm pressure to the lower bench
set pressure. (Or, the upper bench set pressure for
reverse-acting valves.) This should be the same pres-
sure used in the bench set steps, and it is marked on
the nameplate.
4. Place the stem connector half with the threaded
holes, approximately half way between the actuator
Note
Type 667 Size 30-76 & 87
and valve stems. Refer to figures 6, 7, and 8 to help
locate the connector position.
Be sure that the actuator and valve stem threads are
engaging the threads of the stem connector by a dis-
tance equal to one diameter of the stem.
CAUTION
Incomplete engagement of either the
valve stem or actuator stem in the stem
connector can result in stripped threads
or improper operation. Be sure that the
length of each stem clamped in the stem
connector is equal to or greater than one
diameter of that stem. Damage to
threads on either stem or in the stem
connector can cause the parts to be re-
placed prematurely.
5. Install the other half of the stem connector and in-
sert the cap screws and tighten them. If installing a
positioner, also attach the feedback bracket at the
same time.
6. Screw the valve stem locknuts up until the indicator
disk contacts the bottom of the stem connector, or for
size 87 actuators, tighten the locknuts against the
stem connector. Do not overtighten the locknuts.
7. Slowly increase and then decrease pressure sever-
al times, stroking the valve from the lower bench set
pressure to the upper pressure.
Be sure that the valve is in the closed position (up or
down, depending on valve action). Loosen the screws
on the travel scale, and align it with the travel indicator
disk. Stroke the valve full travel to ensure that the trav-
el matches the valve travel on the travel indicator
plate. If valve travel is not correct, repeat the stem
connector procedure.
For push-down-to-close valves, the
valve plug seat is the limit for downward
travel and the actuator up-stop is the
limit for upward (away from the valve)
movement. For push-down-to-open
valves, the actuator down-stop is the
limit for downward movement, and the
valve seat is the limit for upward (away
from the valve) movement. For Type 667
actuators, a down-stop (key 77, figure 6)
is installed to limit actuator diaphragm
downward movement when the actuator
provides the limit.
Note
7