Replacing The Gauges; Replacing The Pressure Control Block; Replacing The Supply Gauge, Proportional, Reset, And Reset Valve Tubing Assemblies; Replacing The Proportional Band Adjustment Knob, Nozzle Assembly, And Set Point Beam Assembly - Fisher 4194B Series Instruction Manual

4194A, B, and C Series
8. Perform the controller calibration procedures and, if
necessary, the appropriate remote set point calibration
procedure in section 3 or 4.
9. Mount the controller as described in the Installation
section.
10. Connect the external piping to the controller.

Replacing the Gauges

CAUTION
Before performing this procedure, be
sure the replacement gauges are the
correct range so that they are not dam-
aged by overpressure.
1. Unscrew the output pressure gauge (key 46) or the
supply pressure gauge (key 47) from the frame (key
3).
2. Before installing the replacement gauge, coat the
threads on the gauge with a sealant such as key 311
or equivalent.
3. Screw the replacement gauge into the frame.
4. Apply the correct supply pressure and check for
leaks with the nozzle capped for full output pressure.

Replacing the Pressure Control Block

1. After bleeding away pressure, remove the process
pressure or remote set point piping from the controller.
2. At the pressure control block (key 57), unscrew the
nut that secures the capsular element tubing so that
the tubing can be removed from the pressure control
block.
3. Remove the two cap screws (key 58) that hold the
pressure control block to the frame, and lift out the
pressure control block.
4. Install the O-ring (key 7) on the replacement pres-
sure control block.
5. Position the replacement pressure control block on
the frame and fasten with the two cap screws (key
58).
6. Insert the tubing from the capsular element into the
pressure control block and tighten the nut loosened in
step 2.
7. Apply pressure equal to the maximum value on the
process scale, and check for leaks.
8. Reconnect the piping, removed in step 1, to the
controller.
5–6
Replacing the Supply Gauge,
Proportional, Reset, and Reset Valve
Tubing Assemblies
1. Remove the controller assembly from the case by
performing steps 1 through 3 of the case and cover
replacement procedures.
2. Unscrew the nuts at each end of the tubing assem-
bly. Remove the tubing assembly.
3. Install the replacement tubing assembly.
4. Set the reset adjustment to 0.01 (4194B and C Se-
ries) and set the rate adjustment to OFF (4194C Se-
ries).
5. Apply the correct supply pressure and check for
leaks with the nozzle capped for full output pressure.
Then, remove the pressure.
6. 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.
7. Perform the controller calibration procedures and, if
necessary, the appropriate remote set point calibration
procedure in section 3 or 4.
8. Mount the controller as described in the Installation
section.
9. Connect external piping to the controller.
Replacing the Proportional Band
Adjustment Knob, Nozzle Assembly, and
Set Point Beam Assembly
Figure 5-3 shows the parts locations for the propor-
tional band adjustment and set point beam. Unless
otherwise noted, refer to this figure while performing
the following procedures.
Disassembly
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 machine screws (key 6), and lift
off the proportional band indicator cover (key 36). See
figure 5-21 for parts location.
3. Disconnect link 3 from the set point beam shoe,
part of the set point beam assembly (key 23).
4. Remove the set point beam bias spring (key 28).
5. Remove the screw and washer (keys 19 and 20)
that hold the adjustable set point pivot assembly (key
17) to the frame, and remove the pivot assembly.
6. Unscrew the nut that secures the relay nozzle tub-
ing assembly (key 18) to the frame manifold (key 135).