Removing Controller From Sensor; Changing Mounting Method; Installing Controller On Sensor - Fisher 2502 Series Level-Trol Instruction Manual

Table 3 lists some common operating faults, their
probable causes, and corrective action.

Removing Controller from Sensor

WARNING
To avoid injury in the following steps,
turn off the supply pressure and careful-
ly 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 16 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 oper-
ating 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).
CAUTION
If the hex nut has not been loosened ac-
cording to step 2, attempting to remove
the controller from the sensor may bend
the rotary shaft or operating arm and
linkage. Be careful that the back of the
controller case or the heat insulator
does not drop down and bend the rotary
shaft or shaft extension.
3. Remove any insulating tape from the joint between
the controller case and the torque tube arm. Remove
he four cap screws (key 39, figure 14) that hold the
controller or heat insulator to the torque tube arm. Pull
the case straight out from the torque tube arm, easing
it over the shaft coupling (key 36, figure 14) if one is
installed.
4. If the controller has a heat insulator, remove the
button head cap screws (key 40). Remove four wash-
ers (key 53) and the insulator assembly (key 35).

Changing Mounting Method

WARNING
To avoid injury from contact with the
process liquid, lower the vessel level
below the torque-tube arm before pro-
ceeding. For closed vessels, release any
pressure that may be above the liquid.
Also, be careful to avoid overloading a
thin-wall torque tube and/or overweight
displacer.
Refer to figure 16 for key number locations.
1. Remove the controller as described previously.
2. A controller is attached to the sensor in one or the
other of the mounting positions shown in figure 4.
Right hand mount is with the case to the right of the
displacer when looking at the front of the case. Left
hand mount is with the case to the left of the displacer.
For a 249 Series sensor, remove the torque tube arm
from the sensor or vessel and reinstall the torque tube
arm in the opposite position according to the appropri-
ate instruction manual.
3. Check the desired control action to determine if it is
also necessary to reverse the controller action. The
nozzle block and bellows tubing should be arranged in
the proper position as shown in figure 15.
4. Remove the raise level dial, turn it over, and install
it in the desired position. The arrow on it under the
word FLOAT should point toward the displacer. On a
controller with indicator assembly, remove two screws
(key 41, figure 16), turn the front plate (key 54, figure
16) to the side that will have the float arrow pointing
toward the displacer, and secure the plate with the
screws.
5. Install the controller according to the next section.

Installing Controller on Sensor

If the installation is in a location that is
not readily accessible and shop calibra-
tion is required, remove the torque tube
arm from the cage or vessel before mat-
ing the controller to the sensor. Install
the controller on the torque tube arm in
the shop; then calibrate and return the
controller and torque tube arm assem-
bly to the installation.
2502 Series
Note
17