Fisher 657 - Manual (Page 8)

Instruction Manual
D100307X012
657 Size 80 and 100 Actuators
December 2010
8
WARNING
To avoid personal injury from the precompressed spring force thrusting the upper diaphragm casing (key 1) away from the
actuator, relieve spring compression (step 2, below), and carefully remove casing cap screws (key 22) (step 4, below).
2. Remove cover band (key 60). Insert a rod of approximately 12.7 mm (1/2‐inch) diameter into a hole in the adjusting
screw (key 12), and rotate the adjusting screw from right to left until spring compression is relieved. If the actuator
has a handwheel, rotate it counterclockwise, relieving all spring compression.
3. If necessary, the entire actuator may be removed from the valve body by unscrewing two cap screws from stem
connector (key 26) and removing actuator‐to‐bonnet bolting.
4. Unscrew diaphragm casing cap screws and nuts (keys 22 and 23), and lift off upper diaphragm casing (key 1).
5. Remove the molded diaphragm (key 2).
6. For actuators without snubber, remove diaphragm plate and stem (keys 4 and 10) as an assembly. This assembly
can be broken down further, if necessary, by removing the cap screw (key 3).
7. For actuators with snubber (see figure 7), unscrew cap screw (key 3), and remove diaphragm plate (key 4). Remove
stem connector (key 26). Unscrew cap screws (key 85), and remove cylinder assembly (key 74) and attached stem
and upper seat (keys 10 and 90) from actuator.
To disassemble snubber:
a. Unscrew stem from piston/piston rod assembly (key 27).
b. Remove retaining rings, cylinder heads, and piston/piston rod assembly (keys 76, 75, and 27). Replace packing
and O‐rings (keys 103, 104, 77 and 105) as required.
8. Remove actuator spring, upper sleeve, and spring seat (keys 6, 34 and 11).
9. Unscrew cap screws and nuts (keys 62 and 63), and remove spring case (key 29). Cap screws (key 62) on units with
side‐mounted handwheel do not use hex nuts (key 63).
10. For actuators without side‐mounted handwheel, remove adjusting flange (key 36) and attached thrust bearing
and adjusting screw (keys 35 and 12).
11. For actuators with side‐mounted handwheel (see figure 7), unscrew cap screws (key 64), and remove adjusting
flange (key 36) and attached thrust bearing and adjusting screw (keys 35 and 12). Do not lose the key (key 47).
Size 80 Assembly
1. Coat the threads of the adjusting flange (key 36) with anti‐seize lubricant (key 244). Replace the adjusting flange,
adjusting screw, and thrust bearing (keys 36, 12, and 35). Pack bearing with lithium grease lubricant (key 241).
For actuators with side‐mounted handwheel, install the key (key 47) on the adjusting flange (key 36). Coat the
adjusting flange threads with anti‐seize lubricant. Install the adjusting flange so that the key engages the slot in the
lower sleeve. Secure adjusting flange with cap screws (key 64). Adjust set screws (key 40, figure 7) to eliminate free
play in handwheel bearings.
Note
Over‐tightening the set screws will make handwheel operation difficult.
2. Mount the spring case (key 29) to the yoke (key 9) using cap screws and hex nuts (keys 62 and 63).