Fisher 4194B Series Instruction Manual page 35

Fault
2. Controlling off set point as
reflected by process and set point
indicators.
3. Controlling off set point but not
reflected by process and set point
indicators.
4. No reset action (4194B and
4194C Series)
5. Abnormal control point shift
when proportional band is changed.
6. Controller will not attain full
output range.
Table 5-1. Troubleshooting Chart (Continued)
Possible Cause
2.7 Reset valve leaks.
2.8 Leak in the remote set point
system (suffix letter M only).
2.9 Input element over pressured.
3.1 Out of calibration
4.1 Reset valve is plugged
4.2 Reset pressure leak
4.3 Tubing leak
5.1 Flapper is dirty or pitted
5.2 Flapper is out of alignment
6.1 Output pressure gauge not
functioning
6.2 Supply pressure not correct
6.3 Proportional band setting two
wide (4194A Series only)
6.4 Input element or linkage failure
6.5 Leak in nozzle pressure tubing
4194A, B, and C Series
Check
2.7 Adjust output to 15 psig (1.0
bar) for a 3 to 15 psig (0.2 to 1.0
bar) output or 30 psig (2.0 bar) for a
6 to 30 psig (0.4 to 2.0 bar) output.
Close the reset valve. If the
controller output varies and no
leaks were found in the rest of the
feedback system (Step 2.6), the
reset valve is leaking.
2.8 Adjust remote set point
pressure to 15 psig (1.0 bar). Using
soap solution, check for leaks in
the remote set point element and
tubing assembly.
2.9 Check for zero shift.
3.1 Refer to the process indicator,
remote set point (if applicable), and
flapper alignment procedures in
section 3 or 4.
4.1 Turn the reset valve through its
range several times to remove any
restrictions.
4.2 Adjust the output to 15 psig (1.0
bar) for a 3 to 15 psig (0.2 to 1.0
bar) output or 30 psig (2.0 bar) for a
6 to 30 psig (0.4 to 2.0 bar) output.
Close the reset valve. If the output
varies and no leaks were found in
the rest of the feedback system
(see Step 2.6), the reset valve is
leaking.
4.3 With reset valve positioned at
0.01 minutes/repeat, put 15 psig
(1.0 bar) to the output port. Using
soap solution, check for leaks in
the reset bellows and attached
tubing assembly.
5.1 Inspect the flapper.
5.2 Refer to flapper alignment
procedures in section 3 or 4.
6.1 Measure the output with an
external pressure gauge.
6.2 Check with an external source.
6.3 Adjust proportional band setting
to 10. Manually cap the nozzle.
Output should increase.
6.4 Inspect the element for
alignment, loose screws and
damaged flexures, links or pivots.
Using soap solution, check the
sensing element for leaks.
6.5 Using soap solution, check for
leaks in the nozzle tubing
assembly.
–Continued–
Correction
2.7 Replace the reset valve.
2.8 Repair or replace parts as
necessary.
2.9 Replace input element and
adjust travel stops.
3.1 Adjust as necessary
4.1 If reset action returns, no
further action is necessary. If not,
replace the reset valve (4194B
Series) or the rate/reset valve
(4194C Series).
4.2 Replace the reset valve (4194B
Series) or the rate/reset valve
(4194C Series)
4.3 Repair or replace parts as
necessary.
5.1 Clean, or replace flapper as
necessary.
5.2 Align flapper as necessary.
6.1 Replace the gauge if it is
defective.
6.2 Repair or replace the supply
pressure regulator, if necessary.
Replace the supply pressure gauge
if necessary.
6.3 Use a narrower proportional
band setting (decrease the
proportional band setting).
6.4 Repair or replace parts as
necessary.
6.5 Replace faulty parts as
necessary. Clean out the relay
primary orifice with the cleanout
wire attached to the relay to ensure
the orifice is not clogged.
5–3