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4194A, B, and C Series
Fault
6. Controller will not attain full
output range.
7. Controller remains at full output
8. Controller remains at zero output
3. Slide the process scale (key 61) downward so that
the top of the slot touches the set point indicator. De-
flect the lower portion of the slot outward and carefully
slide the scale up and off, clearing the set point indica-
tor as shown in figure 5-1.
5–4
Table 5-1. Troubleshooting Chart (Continued)
Possible Cause
6.6 Relay malfunction
7.1 Supply pressure too high
7.2 Output gauge not functioning
7.3 Input element or linkage failure
7.4 Mechanical alignment
7.5 Relay failure or restriction in
nozzle passage
7.6 Flapper misaligned
8.1 Gauge not functioning
8.2 Input element or linkage failure
8.3 Mechanical alignment
8.4 Relay malfunction
8.5 Nozzle pressure leak
Check
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 0.5 psig (35 mbar)
of the supply pressure.
7.1 Check with an external
pressure gauge.
7.2 Vary supply pressure to see if
output gauge responds.
7.3 Vary the process differential
pressure and observe the flapper
for movement. Inspect the input
element and linkage for damage.
7.4 Move the set point and verify
that the nozzle is uncapped by the
flapper. If not, inspect linkages and
flexures for damage.
7.5 Manually move flapper
1/16-inch (1.6 mm) from the nozzle.
7.6 Manually push the flapper away
from the nozzle. Controller output
should go to 0 psig.
8.1 Verify that the supply pressure
is at its correct value and that the
controller output is zero.
8.2 Vary the process differential
pressure and observe the flapper
for movement. Inspect the input
element and linkage for damage.
8.3 Move the set point and verify
that the nozzle is capped by the
flapper. If not, inspect linkages and
flexures for damage.
8.4 Check for air at the nozzle. Cap
the nozzle and note that the
controller output increases to within
0.5 psig of supply pressure.
8.5 Using a soap solution, check
for nozzle tubing leaks with the
nozzle capped by the flapper.
Press the nozzle cap (key 23)
gently to ensure nozzle O-ring (key
24) is sealing. Ensure the relay
nozzle tubing nut (key 18) and the
manifold screws (keys 34 and 131)
are tight.
4. To install the replacement scale, deflect the lower
part of the slot slightly so that the scale slides down-
ward over the set point indicator and under the pro-
cess pointer.
Correction
6.6 If the output does not change
as described, remove the relay.
Replace O-rings, if necessary.
Replace relay, if necessary.
7.1 Replace supply pressure
regulator or gauge as necessary.
7.2 If output gauge does not
respond, replace it.
7.3 Repair or replace parts as
necessary.
7.4 Repair or replace parts as
necessary.
7.5 If the output pressure remains
at the supply pressure, remove the
controller case and cover assembly
and test again with the relay nozzle
tubing nut (key 18) loose. If the
output is 0 psig, clean or replace
the nozzle assembly. If the output
remains at supply pressure, replace
the relay.
7.6 Perform the flapper alignment
procedures in section 3 or 4.
8.1 Replace gauges as necessary
8.2 Repair or replace parts as
necessary
8.3 Repair or replace parts as
necessary
8.4 Clean out the relay primary
orifice with the cleanout wire
attached to the relay to ensure the
orifice is not clogged. If the problem
persists, replace the relay.
8.5 Tighten the relay nozzle tubing
nut (key 18), tighten manifold
screws (keys 34 and 131), or
replace nozzle assembly O-ring or
set point beam assembly as
appropriate.
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