Instruction Manual
D200158X012
4194S Controllers
July 2018
27
Supply Tubing and Positive Feedback Tubing Assemblies
Note
The following procedure requires that the controller be removed from the case. Perform steps 1 through 3 of the replacing case
and cover procedure.
1. Remove the nuts that hold the supply gauge tubing assembly (key 39) or the positive feedback tubing assembly
(key 45) to the frame. Remove the tubing.
2. Install the replacement tubing assemblies.
3. Apply the correct supply pressure, and check for leaks.
4. Install the controller assembly in the case. Slide the controller frame down to assure an O‐ring seal at the pressure
connections. Hold the frame in place.
5. Install and tighten the nine self‐tapping screws (key 38) into the frame.
6. Mount the controller as described in the Installation procedure.
7. Connect supply, output, and process pressure piping to controller.
Proportional Band Knob, Nozzle Pivot, and Set Point Beam Assembly
Note
The following procedure requires that the controller be removed from the case. Perform steps 1 through 3 of the replacing case
and cover procedure.
1. Remove the two screws (key 6) and lift off the proportional band indicator cover (key 36)
3. Remove the set point beam bias spring (key 28). Refer to figure 4-5 for spring location.
4. Remove the screw and washer (keys 19 and 20) that hold the pivot assembly (key 17) to the frame, and remove the
pivot assembly. Refer to figure 4-15.
6. While holding the proportional band knob, remove the screw and washer (keys 19 and 20) that hold the relay
nozzle tubing assembly (key 18) to the frame.
7. Remove the proportional band knob nozzle pivot and the set point beam assembly from controller.
8. Remove the relay nozzle tubing assembly (key 18) from the set point beam assembly (key 23).
9. Remove the E‐ring (key 27) from the nozzle assembly (key 21).
10. Remove the nozzle assembly (key 21) from the bottom of the set point beam assembly (key 23).
11. Remove the retaining clip (key 26).
12. Remove the proportional band knob (key 25) from the set point beam assembly (key 23).
13. Inspect the nozzle pivot O‐ring.
14. Inspect the nozzle assembly (key 21), and replace if necessary. Inspect the nozzle orifice, and clean it if necessary.