Instruction Manual
D200099X012
249 Caged Sensors
April 2017
8
CAUTION
If the displacer is to be disconnected from the displacer rod before being removed from the cage, provide a suitable means
of supporting the displacer to prevent it from dropping into the cage and being damaged.
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. Properly support the assembly to avoid damage to the displacer, displacer
stem, displacer rod/driver assembly, and associated parts.
2. Reach the cotter spring, displacer spud, ball end of the displacer rod/driver assembly, stem end piece, or displacer
stem connector as follows:
All sensors with style 1 or 2 (screwed or flanged) connections
—through the top connection.
249L sensors with style 3 or 4 (screwed or flanged) connections
—by removing the hex nuts (key 33), flange (key
30), and ring (key 31).
All other sensors with style 3 or 4 (screwed or flanged) connections
—by removing the top pipe plug (key 26).
3. Remove the cotter spring to free the displacer or stem end piece from the ball end of the displacer rod/driver
assembly. Lift the displacer or stem end piece from the ball.
4. Replace worn or damaged parts as necessary. Return the displacer or stem end piece to the displacer rod/driver
assembly. Install the cotter spring.
5. 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.
Replacing the Displacer Rod/Driver Assembly
The ball on the displacer rod/driver assembly (key 7) may be either too worn for a secure connection or so corroded
that the displacer does not pivot properly. Replace the displacer rod/driver assembly, if necessary.
CAUTION
If the displacer is to be disconnected from the displacer rod/driver assembly before being removed from the cage, provide a
suitable means of supporting the displacer to prevent it from dropping into the cage and being damaged.
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. Properly support the 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) at the end of the torque tube arm.
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).
