Removing Controller From Sensor - Emerson Fisher 2502 Instruction Manual

2502 Controllers
June 2017
Table 4. Troubleshooting Chart for Fisher 2502 Controllers (continued)
Fault
2. Controller controlling off setpoint
or switching point.
3. Controller cannot attain full
output range.
4. Controller remains at full or zero
output pressure.

Removing Controller from Sensor

WARNING
To avoid personal injury in the following steps, turn off the supply pressure and carefully release any pressure trapped in
the controller before breaking any pressure connection. Provide a bypass for the control device if continuous operation is
required during maintenance.
Refer to figure 14 for key number locations, unless otherwise indicated.
1. Disconnect the supply and output pressure tubing from the controller.
2. Loosen the hex nut (key 40) that secures the operating arm base or pointer assembly (key 68 or 51) to the torque
tube rotary shaft. Do not lose the two link bearings (key 87, not shown).
24
Possible Cause
2.1 Supply pressure not set
correctly.
2.2 Leak in the controller loop.
2.3 Leaking displacer.
2.4 Flapper adjustment.
2.5 Process variable changed.
3.1 Supply pressure not set
correctly.
3.2 Flapper adjustment.
3.3 Process variable changed.
3.4 Relay malfunction.
3.5 Leaking controller loop.
4.1 Supply or output pressure gauge
malfunction
4.2 Flapper adjustment.
Check
2.1 Make sure regulator supply
pressure is set correctly. Make sure
regulator IN supply pressure is within
limits.
2.2 Use soap and water to check for
internal and external leaks.
2.3 Insure the displacer is not filling
with process fluid.
2.4 Insure the flapper is not loose on
the torque tube shaft and is
centered on the nozzle.
2.5 Insure the process variable has
not changed from original
calibration settings or, displacer not
design specific gravity of process.
3.1 Make sure supply pressure is set
correctly. Make sure regulator IN
supply pressure is within limits.
3.2 Insure the flapper is not loose on
the torque tube shaft and is
centered on the nozzle.
3.3 Insure the process variable has
not changed from original
calibration settings or, from
displacer design specific gravity.
3.4 Check for relay malfunction by
using the testing relay deadband
procedure.
3.5 Use soap and water to check for
internal and external leaks.
4.1 Insure the pressure gauges are
registering correctly.
4.2 Insure the flapper is not loose on
the torque tube shaft. Insure the
flapper is centered on the nozzle.
Instruction Manual
D200126X012
Correction
2.1 Reset the supply regulator
pressure. If the condition occurs
again, rebuild or replace regulator.
Provide a regulator input pressure
within regulator limits.
2.2 Replace or repair leaking parts
as necessary.
2.3 Refer to sensor maintenance
procedures in the appropriate sensor
instruction manual.
2.4 Replace or tighten flapper
assembly as necessary and/or center
flapper on nozzle.
2.5 Change process variable back to
original specification or recalibrate.
If necessary, provide replacement
displacer of correct size and
recalibrate.
3.1 Reset the regulator pressure. If
problem reoccurs, replace or rebuild
the regulator. Insure regulator IN
supply pressure is within limits at all
operating levels.
3.2 Replace or tighten flapper
assembly as necessary and/or center
flapper on nozzle.
3.3 Change process variable back to
original specification or recalibrate.
If necessary, provide replacement
displacer of correct size and
recalibrate.
3.4 Depress plunger to clean out the
fixed restriction. Replace relay using
the procedure in the Maintenance
section.
3.5 Replace or repair leaking parts as
necessary.
4.1 Replace pressure gauges. Use
corrective action given in section 3
of this table.
4.2 Replace or tighten flapper
assembly as necessary and/or center
flapper on nozzle.