Instruction Manual
D200156X012
4194HA, HB, HC Controllers
July 2018
40
Table 5‐1. Troubleshooting Chart (Continued)
Fault Possible Cause Check Correction
3. Controlling off set
point but not reflected
by process and set
point indicators.
3.1 Out of calibration. 3.1 Refer to the calibration and flapper
alignment procedures.
3.1 Adjust as necessary.
4. No reset action
(4194HB and 4194HC
controllers).
4.1 Reset valve is plugged. 4.1 Turn the reset valve through its range
several times to remove any restrictions.
4.1 If reset action returns, no further action is
necessary. If not, replace the reset valve
(4194HB) or rate/reset valve (4194HC).
4.2 Reset pressure leak. 4.2 Adjust the output to 1.0 bar (15 psig) for
a 0.2 to 1.0 bar (3 to 15 psig) output or 2.0
bar (30 psig) for a 0.4 to 2.0 bar (6 to 30 psig)
output. Close the reset valve. If the output
varies and no leaks were found in the rest of
the feedback system (see Step 2.7), the reset
valve is leaking.
4.2 Replace the reset valve if necessary.
4.3 Tubing leak. 4.3 With reset valve positioned at 0.01
MIN/repeat put 1.0 bar (15 psig) to the
output port. Using soap solution, check for
leaks in the reset bellows and attached
tubing assembly.
4.3 Repair or replace parts as necessary.
5. Abnormal control
point shift when
proportional band is
changed.
5.1 Flapper is dirty or
pitted.
5.1 Inspect the flapper. 5.1 Clean, or replace flapper as necessary.
5.2 Flapper is out of
alignment.
5.2 Refer to flapper alignment procedures. 5.2 Align flapper as necessary.
6. Controller will not
attain full output
range.
6.1 Output pressure
gauge not functioning.
6.1 Measure the output with an external
pressure gauge.
6.1 Replace the gauge if it is defective.
6.2 Supply pressure not
correct.
6.2 Check with an external source. 6.2 Repair or replace the supply pressure
regulator, if necessary. Replace the supply
pressure gauge if necessary.
6.3 Proportional band
setting too wide (4194HA
controllers only).
6.3 Adjust proportional band setting to 10.
Manually cap the nozzle. Output should
increase.
6.3 Use a narrower proportional band setting.
6.4 Differential pressure
unit or linkage failure.
6.4 Inspect the linkages for misalignment,
loose screws, and damaged links or pivots.
Using soap solution, check for leaks. Refer to
the differential pressure unit instruction
manual.
6.4 Repair as necessary.
6.5 Leak in nozzle pressure
tubing.
6.5 Using soap solution, check for leaks in the
nozzle tubing assembly.
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.
6.6 Relay malfunction 6.6 Manually push the flapper away from the
nozzle. The output pressure should be zero.
Cap the nozzle. The output should increase
rapidly to within 0.03 bar (0.5 psig) of the
supply pressure.
6.6 If the output does not change as described,
remove the relay. Replace O‐rings, if necessary.
Replace relay, if necessary.
7. Controller remains
at full output.
7.1 Supply pressure too
high.
7.1 Check with an external pressure gauge. 7.1 Supply pressure regulator or gauge may have
to be replaced.
7.2 Output gauge not
functioning.
7.2 Vary supply pressure to see if output
gauge responds.
7.2 If output gauge does not respond, replace it.
7.3 Differential pressure
unit or linkage failure.
7.3 Vary the process differential pressure and
observe the flapper. Inspect the linkages for
damage. Refer to the differential pressure
unit instruction manual.
7.3 Repair or replace parts as necessary.
7.4 Mechanical alignment. 7.4 Move the set point and verify that the
nozzle is uncapped by the flapper. If not,
inspect linkages for damage.
7.4 Repair or replace parts as necessary.
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