Replacing The Proportional Band Adjustment Knob, Nozzle Assembly, And Set Point Beam Assembly - Emerson Fisher 4194HA Instruction Manual

4194HA, HB, HC Controllers
July 2018
Replacing the Proportional Band Adjustment Knob, Nozzle Assembly, and Set Point Beam
Assembly
Note
Before starting the following procedure, remove the controller from the case. Perform steps 1 through 7 of the Replacing the
Differential Pressure Unit procedure. Then, perform steps 1 and 2 of the Replacing the Case and Cover procedure.
Key numbers refer to figure 6‐1.
Disassembly
1. Perform the procedures required in the Note above.
2. Remove the two screws (key 6) and lift off the proportional 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 5‐9 for
location of the link/shoe.
4. Remove the set point beam bias spring (key 28). Refer to figure 5‐9 for spring location.
5. Remove the screw and washer (keys 19 and 20) holding the bracket of the set point pivot assembly to the frame.
Remove the pivot assembly from the set point beam assembly.
6. Disconnect the nut holding the relay nozzle tubing into the frame manifold (key 3).
7. While holding the proportional band knob, remove the screw and washer (keys 19 and 20) which holds the bracket
of the relay nozzle tubing assembly (key 18) to the frame.
8. Remove the proportional band knob nozzle pivot and set point beam assembly from the controller frame.
9. Pull the relay nozzle tubing assembly (key 18) from the bore in the set point beam assembly (key 23).
10. Remove the E‐ring (key 27) holding the retaining clip, proportional band knob, and nozzle assembly together with
the set point beam assembly.
11. Pull the nozzle assembly (key 21) from the set point beam assembly. Do not lose the plastic washer (key 22).
12. Remove the retaining clip (key 26).
13. Remove the proportional band knob (key 25) from the set point beam assembly (key 23). Do not lose the plastic
washer (key 22).
14. Inspect the nozzle assembly O‐ring. Replace it, if necessary.
15. First, inspect the nozzle orifice and clean it, if necessary. Then, inspect the entire nozzle assembly (key 21) and
replace it, if necessary.
Assembly
1. Lubricate (key 318) and install the proportional band knob (key 25) on the set point beam assembly (key 23).
2. Install the retaining clip (key 26) on the three posts on the proportional band knob.
3. Lubricate the nozzle assembly O‐ring and install the nozzle assembly (key 21) through the set point beam assembly
(key 23), the proportional band knob (key 25) and the retaining clip (key 26) into the cap, aligning the nozzle with
the tab on the proportional band knob (shown in figure 5‐10).
4. While holding the nozzle tubing (key 21) against the set point beam assembly (key 23), depress the retaining clip
(key 26) and install the E‐ring (key 27) into the E‐ring groove on the nozzle tubing assembly (key 18). Be sure all
three corners of the E‐ring are engaged.
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Instruction Manual
D200156X012