Instruction Manual
D200099X012
249 Caged Sensors
April 2017
10
1. After following the proper procedure to remove the cage head and the displacer from the cage, move the sensor
assembly to a suitable maintenance area.
CAUTION
Support the sensor assembly to avoid damage to the displacer, displacer stem, displacer rod assembly, and associated
parts.
2. Remove the controller/transmitter and displacer (key 10). Then, remove the hex nuts (key 20) that hold the torque
tube arm (key 3) to the cage head (key 2). Separate the torque tube arm from the cage head.
3. Remove the nuts (key 18) and retaining flange (key 6) holding the positioning plate (key 8) at the end of the torque
tube arm.
CAUTION
If the displacer is still attached to the displacer rod at this point, be careful not to let the torque tube assembly slip when
using the screwdriver leverage procedure in steps 4 and 6. Sudden release of the displacer could cause damage.
4. Remove the positioning plate (key 8) by freeing its two lugs.
The vertical lug fits into a hole in the flange of the torque tube arm (top of figure 6, left). The horizontal lug (hidden
behind the screwdriver at the bottom of figure 6, left) fits into a slot in the outer tube end of the torque tube
assembly (the figure 6 exploded view shows this lug to the right of the outer tube end).
The positioning plate may be pried away from the torque tube arm and outer tube end if the displacer already has
been disconnected from the displacer rod. However, if the displacer is still connected to the displacer rod, place a
screwdriver blade in the slots of the positioning plate and outer tube end as shown in figure 6. Slowly turn the
positioning plate to release its lug from the torque tube arm. Then carefully turn the plate back to allow the
displacer to come to rest, and slip the other lug of the plate from its slot in the outer tube end.
5. Pull the torque tube assembly and tube end gasket out of the torque tube arm. Remove the tube end gasket
(key 14) and discard (a new gasket will be installed in step 6). Clean and inspect the gasket mating surfaces.
6. Insert new tube end gasket into recess in torque tube arm.
7. Insert the torque tube assembly into the torque tube arm as shown in figure 6. Rotate the torque tube assembly
until its socket mates with the driver member on the displacer rod assembly and so that the outer tube flange rests
against the gasket. With a thumb on the upper portion of the positioning plate and a screwdriver in the slots as
shown in figure 6, rotate the plate and press the lug on the plate into the hole in the torque tube arm (this will
preload the torque tube).
8. Install the retaining flange and secure it with four nuts (key 18), being sure to tighten all nuts evenly.
9. If necessary, clean the cage following the procedure in this manual. Install the cage head and controller/transmitter.
Properly calibrate the controller/transmitter following the procedures given in the controller/transmitter
instruction manual.
Changing Cage Head Position
The cage head (key 2) may be mounted so that the torque tube arm (key 3) is in any one of eight alternate positions
around the cage as shown in figure 7. Neither the displacer nor the torque tube arm need be removed when head
position is changed.
