Emerson Fisher 657 Instruction Manual page 8

657 Actuator (30/30i-70/70i and 87)
June 2018
WARNING
Install the stem connector securely before a positioner is mounted to the actuator and pressurized, using only a
regulator-controlled air supply, not the positioner, to move the actuator stem.
To avoid personal injury or property damage, keep hands and tools out of the actuator stem travel path while applying
loading pressure to move the actuator stem in the following steps.
CAUTION
To avoid damaging the seating surfaces, do not rotate the valve plug while it is seated. Exercise care while installing the
stem connector assembly to avoid damage to the valve plug stem and valve stem threads.
Note
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, if present, before clamping the actuator and valve stems together. Use only a mated pair
of stem connector halves.
1. If necessary, push the valve stem down so that it is touching the seat ring on direct acting valves. For reverse acting
valves, push the stem down to the open position.
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 14) is located on top of the locknuts.
2. Slowly increase the diaphragm pressure to the upper bench set pressure. This should be the same pressure used in
the Spring Verification steps, and it is marked on the nameplate.
3. Place the stem connector half with the threaded holes, approximately half way between the actuator and valve
stems, and align with the stem connector. A slight change to loading pressure may be necessary to align the
threads. Refer to figures 6, 7, 8, 9, and 10 to help locate the connector position.
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 replaced
prematurely. Do not loosen the cap screws when the stem connector has spring or loading pressure force applied.
4. Install the other half of the stem connector and insert the cap screws and tighten them while ensuring even spacing
between the stem connector halves on all sides. If installing a positioner, also attach the feedback bracket at the
same time.
CAUTION
Over‐tightening the valve stem locknuts can make disassembly difficult.
8
Instruction Manual
D100306X012