Instruction Manual
D100291X012
480 Series Actuators
August 2012
8
481
The 481 actuator also requires 1/4 NPT external supply pressure piping. The 481 has only a pressure tap cover on top
of the cylinder. Supply air pressure must be connected to it, and also to the lower cylinder connection located near the
cylinder/cylinder flange joint. An external four-way valve or other switching device must be provided between the
main supply pressure line and these two actuator pressure connections.
Adjustments
All three adjustments on the 480 actuator are on the 3570 positioner. For further information on the positioner, such
as Adjustments, Maintenance, Reversing, and Relay Operation,refer to the Fisher 3570 instruction manual,
D200137X012.
The 481 actuator requires no adjustments.
Actuator Maintenance
WARNING
Avoid personal injury from sudden release of process pressure. Before performing any maintenance operations:
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Do not remove the actuator from the valve while the valve is still pressurized.
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Always wear protective gloves, clothing, and eyewear when performing any maintenance operations to avoid personal
injury.
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Disconnect any operating lines providing air pressure or a control signal to the actuator. Be sure the actuator cannot
suddenly open or close the valve.
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Use bypass valves or completely shut off the process to isolate the valve from process pressure. Relieve process pressure
on both sides of the valve. Drain the process media from both sides of the valve.
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Use lock-out procedures to be sure that the above measures stay in effect while you work on the equipment.
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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.
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Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
It is necessary for efficient and proper operation of the actuator that all parts be free from dirt, abrasives, and foreign
material. Upon assembly at the factor, all synthetic rubber O-rings have been coated with water-resistant lithium
grease. It is recommended that this lubricant be used on all O-rings, especially those on moving parts or in contact
with moving parts, whenever the actuator is dismantled.
Disassembly
Refer to figures 7 and 8.
References to “positioner” can be ignored if a 481 actuator is involved.
