Emerson Fisher 4194S Instruction Manual page 23

Instruction Manual
D200158X012
Table 4-1. Troubleshooting Chart
Fault
1. Output does not snap when
process pointer and set point
indicator are aligned.
2. Controller output will not snap to
full output pressure
3. Controller output will not snap to
zero pressure
Changing Controller Action
The following steps describe changing controller action from direct (increasing process pressure produces increasing
output pressure) to reverse (increasing process pressure produces decreasing output pressure or vice versa.
1. Loosen two screws (key 6) in the proportional band indicator cover (key 36). The screws need not be removed.
2. Lift the proportional band indicator cover as shown in figure 4-2.
3. Rotate the proportional band knob (key 25) to the desired controller action.
4. Install the proportional band indicator cover (key 36), and tighten the two screws (key 6).
Possible Cause
1.1 Flapper out of alignment
1.2 Process pointer not calibrated
correctly
1.3 No supply pressure
1.4 Leak in nozzle or feedback
tubing
1.5 Leak in relay O‐rings
2.1 Output pressure gauge not
functioning
2.2 Supply pressure incorrect
2.3 Leak in positive feedback tubing
2.4 Leak in nozzle tubing assembly
2.5 Sensing element or linkage
failure
2.6 Relay malfunction
2.7 Switching point has not been
reached
2.8 Link 4 not adjusted correctly
3.1 Flapper out of alignment
3.2 Switching point has not been
reached
3.3 Sensing element or linkage
failure
3.4 Links 2, 3, and 4 defective
3.5 Relay malfunction or clogged
nozzle
Check
1.1 Refer to Flapper Alignment
procedures
1.2 Refer to the Process Zero and
Span Adjustment procedures
1.3 Check supply pressure
1.4 Using a soap solution, check for
leaks
1.5 Using a soap solution, check for
leaks
2.1 Check output with external
gauge
2.2 Check with an external source
2.3 Using soap solution, check for
leaks
2.4 Using soap solution, check for
leaks
2.5 Inspect element or linkage for
damaged parts
2.6 Manually cap the nozzle output
by pushing the flapper toward the
nozzle. Output should go to supply
pressure.
2.7 Refer to the Flapper Alignment
or to the Setting Switching Points
procedure
‐ ‐ ‐
3.1 Refer to the Flapper Alignment
procedure
3.2 Refer to the Setting Switching
Points procedure
3.3 Inspect sensing element and
linkage for damaged parts. Using
soap solution, check for leaks.
3.4 Inspect links for loose screws and
improper connections. Ensure links
are not rubbing or catching on other
parts.
3.5 Manually push the flapper away
from the nozzle. The output should
go to zero.
4194S Controllers
July 2018
Correction
1.1 Align flapper as necessary
1.2 Adjust as necessary
1.3 Provide correct supply pressure
1.4 Repair or replace defective parts
1.5 Repair or replace defective
O‐rings
2.1 Replace gauge if necessary
2.2 Repair or replace pressure
regulator if necessary
2.3 Replace defective parts as
necessary
2.4 Replace defective parts as
necessary
2.5 Repair or replace damaged parts
2.6 If output does not change as
described, remove relay. Replace
O‐rings if necessary. Replace relay if
necessary.
2.7 Make alignments and
adjustments as necessary
2.8 Refer to the maintenance
procedures for link adjustment
3.1 Align flapper as necessary
3.2 Adjust switching as necessary
3.3 Repair or replace faulty parts
3.4 Replace links as necessary
3.5 Replace the relay. If the output
still does not go to zero, replace the
nozzle pivot assembly
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