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Instruction Manual
D103472X012
Maintenance
Normally, only the elastomeric parts and the spring of the 667NS2 actuator require inspection or replacement. The
maintenance instructions are divided into three subsections: Replacement of Elastomeric Parts, Disassembly, and
Assembly. Perform only those steps applicable to the actuator size and required maintenance.
It is recommended that the diaphragm and all of the other elastomeric parts of the 667NS2 actuator be inspected
every two outages. The absolute maximum replacement period for any of the elastomeric parts is six years.
All maintenance operations can be performed with the valve in the line.
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 Always wear protective gloves, clothing, and eyewear when performing any maintenance operations to avoid personal
injury.
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.
D The valve packing box may contain process fluids that are pressurized, even when the valve has been removed from the
pipeline. Process fluids may spray out under pressure when removing the packing hardware or packing rings.
D Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
Replacement of Elastomeric Parts
The elastomeric parts in a size 45, 70, or 80 actuators include the diaphragm and Orings. Because replacement of
these parts necessitates complete disassembly, perform the steps outlined in the procedures for disassembly and
assembly of size 45, 70, and 80 actuators.
Disassembly
Size 45 and 70 Actuators
Key number references are shown in figure 4 for size 45 and 70 actuators.
1. Bypass the control valve. Reduce the actuator loading pressure to atmospheric pressure, and remove the tubing or
piping from the connection in the yoke (key 109).
WARNING
To avoid personal injury due to the sudden, uncontrolled movement of parts, do not loosen the stem connector cap screws
on the stem connector (key 103) when spring force is applied.
667NS2 Actuator
March 2022
15
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