Loading Connection; Maintenance; Actuator Maintenance - Emerson Fisher 3025 Instruction Manual

3025 Actuator
May 2011
11. If the actuator is equipped with a side-mounted handwheel, insert the screw (key 139) and the nut (key 140) into
the stem connector half (key 78). Then screw the nut against the stem connector half. Adjust the handwheel travel
indicator (key 113) to correspond with the screw (key 139) used as neutral position indicator. It may be necessary
to take off the protective covers (key 119) by removing the cap screws and washers (keys 120 and 128). Once
adjusted, replace the protective covers, washers and tighten the screws.

Loading Connection

The loading pressure connections are made at the factory if the valve, actuator, and positioner come as a unit. Keep
the length of tubing or piping as short as possible to avoid transmission lag in the control signal. If a volume booster,
valve positioner or other accessory is used, be sure that it is properly connected to the actuator. Refer to the positioner
instruction manual or other manuals as necessary.
For actuators shipped separately or whenever the actuator pressure connections are installed, use the following steps:
1. Connect the loading pressure piping to the NPT internal connection at the side of the diaphragm casing.
2. Cycle the actuator several times to be sure that the valve stem travel is correct when the correct pressure ranges
are applied to the diaphragm.
3. If valve stem travel appears to be incorrect, refer to the travel stop adjustment procedures at the beginning of this
section. Do not place the valve in service if it is not reacting correctly to diaphragm loading pressure changes.

Maintenance

Actuator parts are subject to normal wear and must be inspected and replaced when necessary. The frequency of
inspection and replacement depends on the severity of service conditions.
WARNING
Avoid personal injury or property damage from sudden release of process pressure or bursting of parts. Before performing
any maintenance operations:
D Do not remove the actuator from the valve while the valve is still pressurized.
D Disconnect any operating lines providing air pressure, electric power, or a control signal to the actuator. Be sure the
actuator cannot suddenly open or close the valve.
D Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure
from both sides of the valve. Drain the process media from both sides of the valve.
D Vent the power actuator loading pressure and relieve any actuator spring precompression.
D Use lock-out procedures to be sure that the above measures stay in effect while you work on the equipment.
When performing maintenance procedures, isolate the control valve from the process line pressure from both sides of
the valve. Use the lock-out procedures to be sure that the above measures stay in effect while you are working on the
actuator.

Actuator Maintenance

This procedure describes how the actuator can be completely disassembled and assembled. When inspection or
repairs are required, disassemble only those parts necessary to accomplish the job; then, start the assembly at the
appropriate step.
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Instruction Manual
D251402X012