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4194A, B, and C Series
41. Remove the tape and move the process pointer
until the controller output equals the pressure recorded
in step 39. Note the process pressure indication.
42. The process pressure indication should be within
2 percent of the upper limit on the process scale.
If the process pressure indication in step 41 is greater
than the upper limit of the process scale by 2 percent,
loosen the shoe adjustment screws (key 30), shown in
figure 5-3, and move the set point beam shoe (key 29)
slightly away from the center of the flapper assembly.
If the process pressure indication in step 41 is less
than the upper limit of the process scale by 2 percent,
loosen the shoe adjustment screws (key 30), shown in
figure 5-3, and move the setpoint beam shoe (key 29)
slightly toward the center of the flapper assembly.
43. Repeat steps 38 through 42 until the error is less
than 2 percent of the process scale range at the upper
limit of the process scale.
44. Remove the tape from the process pointer and
reconnect link 1 to the input element. Be sure to re-
connect link 1 in the same hole noted in step 39.
45. Position the controller assembly in the case and
start, but do not tighten the nine mounting screws.
Slide the controller assembly down to assure an O-
ring seal at the pressure connections along the bottom
of the case. Hold the controller assembly in place
while tightening the nine mounting screws.
46. Perform the controller calibration procedures and,
if necessary, the appropriate remote set point calibra-
tion procedure in section 3 or 4.
47. Mount the controller as described in the Installa-
tion section.
48. Connect external piping to the controller.
Replacing the Flapper Assembly and
Flapper Flexure Pivot Assembly
1. Remove the controller assembly from the case by
performing steps 1 through 3 of the case and cover
replacement procedures.
2. Remove the two screws (key 6), and lift off the pro-
portional band indicator cover (key 36).
3. Disconnect link 3 from the set point beam shoe,
part of the set point beam assembly (key 23). Refer to
figure 5-3 for the link location.
4. Remove the set point beam bias spring (key 28),
refer to figure 5-3 for the spring location.
5. Remove the screw and washer (keys 19 and 20)
that hold the adjustable set point pivot assembly (key
17) to the frame.
6. Remove the adjustable set point pivot assembly
(key 17).
5–10
7. Unscrew the nut that secures the relay nozzle tub-
ing assembly (key 18) to the frame manifold (key 135).
Refer to figure 5-3.
8. While holding the proportional band adjustment
knob, remove the screw and washer (keys 19 and 20)
that hold the relay nozzle tubing assembly (key 18) to
the frame.
9. Remove the proportional band adjustment knob,
relay nozzle tubing assembly, and the set point beam
assembly from the controller.
10. Disconnect link 2 from the flapper assembly (key
11). Refer to figure 5-7 for the link location.
11. Disconnect link 4 from the bellows bracket (key
31). Refer to figure 5-7 for the link location.
12. Remove the two cap screws (key 12) from the
flexure pivot assembly (key 9). See figure 5-8 for
screw location.
13. Remove the flapper assembly and link 4 as shown
in figure 5-9.
14. Remove the four machine screws (key 10) shown
in figure 5-9 that hold the flexure pivot assembly to the
frame.
15. Remove the flexure pivot assembly (key 9).
16. Install the replacement flexure pivot assembly
with the four screws (key 10). Do not tighten the
screws.
17. With the controller in the upright position, move
the flexure pivot assembly down as far as possible,
and tighten the four screws (key 10).
18. Place the flapper assembly (key 11) on the flexure
pivot assembly (key 9) with link 4 through the hole in
the frame.
19. Position the flapper assembly (key 11) on the flex-
ure pivot assembly (key 9) and start the cap screws
(key 12) that hold the flapper assembly to the flexure
pivot assemby. Do not tighten the screws.
20. Align flapper leveling screw number 2 with the
centerline of the oblong hole in the frame as shown in
figure 5-8. Tighten the cap screws (key 12).
The following procedure (steps 21
through 23) adjusts link 2 to ensure that
it will always be in tension to eliminate
possible instability due to lost motion.
21. Disconnect link 1 from the input element, noting
the hole location, and manually position the process
pointer to the process scale upper limit. Tape the
pointer in this position.
22. Adjust the length of link 2 by turning the adjust-
ment screw, shown in figure 5-10, clockwise to in-
Note
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