Actuator Mounting - Fisher 685SE Instructions Manual

Instruction Manual
D103799X012

Actuator Mounting

The following procedure describes how to mount a 685SE or 685SR actuator on a push­down­to­close valve so that
the piston rod to valve plug stem connection allows full travel and proper shutoff. Key numbers referenced in the
following steps are shown in figures 3, 4, 5, and 6.
CAUTION
The 685SE actuator spring load will force the piston rod to extend out of the cylinder, and it can come into contact with the
valve stem during actuator mounting.
If the valve stem is allowed to remain in the up position (towards the actuator) during mounting, it can interfere with the
actuator mounting, possibly damage valve stem threads or bend the valve stem. Be sure the valve stem is pushed down
(into the valve body), away from the actuator while mounting.
To avoid damaging the valve plug seating surfaces, do not rotate the valve plug while it is seated. Also avoid damage to the
valve plug stem by careful use of tools during travel adjustment.
For 685SE actuators only: It may be necessary to apply a temporary loading pressure to the bottom cylinder pressure
connection to move the piston rod away from the valve stem during installation. If it is not possible to provide a
temporary loading pressure, exercise caution when lowering the actuator over the valve stem to prevent damage to
the valve stem or piston rod.
WARNING
When moving the piston rod with loading pressure applied, exercise caution to keep hands and tools out of the piston rod
travel path. If the loading pressure is accidentally disconnected, personal injury and property damage is possible if
something is caught between the piston rod and other control valve parts.
1. For 685SE Actuators: Using the lifting points along the outside perimeter of the outer spring cartridge (key 23)
attach appropriate rigging gear to both lifting points.
For 685SR Actuators: Thread two lifting eyes into the free ports on the upper head (key 1) 180 degrees apart.
Reference tables 4 and 5 for approximate weights of the actuator to select an appropriate lifting eye. Attach
appropriate rigging gear to the lifting eyes.
2. Lower the actuator onto the valve bonnet.
a. For the 90.5 mm (3­9/16 inch) yoke boss: Slowly lower the actuator down onto the valve. As the yoke passes over
the end of the valve stem, place the yoke locknut over the valve stem. Once the actuator is in place, screw the
yoke locknut onto the valve bonnet and tighten.
b. For all other yoke bosses: Slowly lower the actuator down onto the valve. Once the actuator is in place, insert the
bonnet­to­actuator bolts and tighten the hex nuts.
3. Turn the two stem locknuts (if present) all the way onto the valve stem thread.
4. Starting with the piston rod fully retracted, manually, or with air pressure, extend the piston rod to the specified
valve travel.
5. Attach the stem connector (key 18), clamping the piston rod (key 17) to the valve stem. Be sure to also attach the
feedback arm and travel indicator.
6. Cycle the actuator to check availability of desired total travel and that the valve plug seats before the cylinder
reaches the end of its stroke. You can make minor travel adjustments, if necessary, by loosening the stem
connector slightly, tightening the locknuts together, and (with the valve plug off the seat) screwing the stem
connector either into or out of the stem connector by means of a wrench on the locknuts.
685SE/685SR Piston Actuator
June 2017
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