Table of Contents
Advertisement
Instruction Manual
D104496X012
Installing the Stem Connector Assembly
When installing the stem connector assembly (key 26), the actuator and desuperheater stem threads should engage
the threads of the stem connector by the distance equal to the diameter of the stem.
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 desuperheater plug while it is seated. Exercise care while
installing the stem connector assembly to avoid damage to the desuperheater plug stem and desuperheater 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 desuperheater stems together. Use only a
mated pair of stem connector halves.
1. Pull the desuperheater stem up so that it is touching the seat ring.
If necessary, screw the desuperheater stem locknuts down, away from the connector location. For all actuators,
ensure that the travel indicator disk (key 14) is located on top of the locknuts.
2. Actuator should be at lower bench set.
3. Place the stem connector half with the threaded holes, approximately half way between the actuator and
desuperheater stems, and align with the stem connector. A slight change to loading pressure may be necessary to
align the threads. Refer to figure 7 to help locate the connector position.
CAUTION
Incomplete engagement of either the desuperheater 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 lubricated 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 desuperheater stem locknuts can make disassembly difficult.
657C Actuator (40i, 46i, and 60i)
November 2019
9
Advertisement
Table of Contents
