Maintenance - Fisher 685 Instruction Manual

Instruction Manual
D103626X012
1. Open the bypass valve.
2. Rotate the handwheel (key 45) to position the override engage pin (key 38) with the hole in the stem connector
(key 10). Turn the engage pin control knob (key 33) clockwise to insert the override engage pin into the stem
connector until it stops.
Note
Depending on construction , the handwheel may have operation information stamped into the part. Always refer to steps 3 and 4
for operation information specific to push-down-to-close and push-down-to-open valves.
3. For a push­down­to­close valve: Rotate the handwheel (key 45) clockwise to close the valve and counterclockwise
to open the valve.
4. For a push­down­to­open valve: Rotate the handwheel (key 45) counterclockwise to close the valve and clockwise
to open the valve.
5. To disengage the manual handwheel, rotate the handwheel (key 45) to relieve any load placed on the override
engage pin (key 38), turn the engage pin control knob (key 33) counter-clockwise until it stops.
Table 6. Turns-Per-Inch of Travel Specifications

Maintenance

WARNING
Avoid personal injury from sudden release of process pressure. 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
on both sides of the valve. Drain the process media from both sides of the valve.
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, or when
loosening the packing box pipe plug.
D Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
Instructions are given below for complete disassembly of the actuator, seal replacement, and O­ring replacement.
When inspection or repair is necessary, disassemble the actuator only as far as is required to accomplish the job. Key
numbers referenced in the following steps are shown in figures 2 and 3.
Actuator Size
12
14 to 18
20 to 22
24 to 26
685 Piston Actuator
Turns of Handwheel Per Inch of Travel
96
80
72
72
May 2013
7