Replacing Link 5 - Fisher 4194B Series Instruction Manual

CLINCH
NUT
W4191-1 / IL
Figure 5-15. Flapper Leveling Screw and Clinch Nut
BELLOWS BRACKET
(KEY 31)
W4195 / IL
Figure 5-16. Position of Link 4 Adjustment Screws
2. Disconnect link 4 from the bellows bracket (key 31)
and the flapper assembly (key 11).
3. Connect the replacement link to the flapper assem-
bly so that the two adjusting screws on the link are
nearest to the bellows bracket (key 31) and so that the
screw heads are facing the bottom of the controller as
shown in figure 5-16.
4. For controllers with reset (4194B Series) or reset
and rate adjustments (4194C Series), turn the reset
adjustment to the CLOSED (4194B) or OFF (4194C)
position. Turn the rate adjustment (4194C Series) to
the OFF position.
The controller output must be 0 psig (0 bar). To be
sure the controller output is at 0 psig (0 bar), remove
supply pressure, set the reset adjustment to 0.01 min-
utes per repeat and wait 30 seconds; then, turn the
FLAPPER LEVELING
SCREW
LINK 4 ADJUSTMENT
SCREW HEADS
4194A, B, and C Series
reset adjustment to the CLOSED (4194B) or OFF
(4194C) position.
5. For controllers with reset (4194B Series) or reset
and rate adjustments (4194C Series), disconnect the
tubing that connects the reset bellows to either the
reset restriction valve (key 54) or the rate/reset valve
assembly (key 262). Make this disconnection at the
valve.
6. Adjust the proportional band to 5 percent RE-
VERSE and move the set point indicator to the pro-
cess scale upper limit.
7. Disconnect link 1 from the pivot arm. Tape the pro-
cess pointer to the process scale lower limit (the last
mark on the left side of the scale).
8. Apply the correct supply pressure to the controller.
The output of the controller should be within 2 psig
(0.14 bar) of supply pressure. If not, adjust flapper lev-
eling screw 1 (the screw nearest the nozzle) until the
output is within 2 psig (0.14 bar) of supply pressure.
9. Loosen the two adjusting screws on link 4. Connect
the free end of the link to the bellows bracket and al-
low the link to find its free length.
10. Tighten the two adjusting screws on the link.
11. Raise link 4 out of the hole in the bellows bracket
(key 31) and ensure that it drops back into the hole
under its own weight. If not, repeat steps 9 and 10.
12. For a controller with reset (4194B or C Series),
reconnect the reset tubing assembly (key 43) to the
reset restriction valve or to the rate/reset valve.
13. For a controller with reset, adjust the reset adjust-
ment to 0.01. The rate adjustment (4194C) should re-
main in the OFF position.
14. The controller output should be within 2 psig (0.14
bar) of the supply pressure. If not, adjust flapper level-
ing screw 1 (the screw nearest the nozzle) until the
output is within 2 psig (0.14 bar) of supply pressure.
15. Check the reset tubing for leaks and tighten if
necessary.
16. Remove the tape from the process pointer and
connect link 1 to the pivot arm.
17. Perform the controller calibration procedures and,
if necessary, the appropriate remote set point calibra-
tion procedure in section 3 or 4.

Replacing Link 5

1. Note the location of the connection holes and dis-
connect both ends of link 5 (key 88) from the lever
arms of the two pivot assemblies. Refer to figure 5-17
for parts locations.
2. Loosen the adjustment screw on the replacement
link, and adjust the length to match the original link.
Tighten the adjustment screw.
5–19