Instruction Manual

Instruction Manual

D102803X012

249W Sensor

December 2012

CAUTION

When removing the sensor from a process vessel or displacer cage, the displacer may remain attached to the displacer rod

and be lifted out with the wafer body (key 1) when the wafer body is removed. If separating the displacer and displacer rod

before removing the wafer body, remove the cotter spring (key 10).

Be careful not to let the displacer slip and drop into the bottom of the process vessel or displacer cage, as displacer damage

could result.

2. Carefully remove the sensor. If the displacer comes out with the sensor, be careful not to damage the displacer or

bend the stem when setting the sensor down.

3. Follow the procedure for replacing the displacer, displacer rod assembly, cotter spring, stem end piece, and

displacer spud as necessary.

Replacing the Displacer, Cotter Spring, Stem End Piece, and Displacer

Spud

The cotter spring (key 10), the ball on the displacer rod/driver assembly (key 5), and the stem end piece or displacer

stem connector (key 6) may be either too worn for a secure connection or so clogged or corroded that the displacer

does not pivot properly. Replace these parts, as necessary.

CAUTION

If the displacer is to be disconnected from the displacer rod before being removed from the process vessel or displacer

cage, provide a suitable means of supporting the displacer to prevent it from dropping into the vessel or cage and being

damaged.

1. After following the proper procedure to remove the sensor and the displacer from the process vessel or displacer

cage, move the sensor assembly to a suitable maintenance area. Support the assembly to avoid damage to the

displacer, displacer stem, displacer rod/driver assembly, and associated parts.

2. To help support the displacer, install the stem and stem end piece (or a threaded rod) into the 1/4 inch‐28 UNF

threaded hole in the displacer spud or stem connector.

3. Reach the cotter spring, displacer spud, ball end of the displacer rod/driver assembly, stem end piece, or displacer

stem connector as follows:

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. Install the sensor and controller/transmitter. 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 5) 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.