Emerson Rosemount OCX 8800 Reference Manual page 240

Maintenance and service
M.
Do not attempt to replace the O
been considered. If cell replacement is needed, order the O
Chapter
The O
cap, screws, and anti-seize compound. The items are carefully packaged to preserve
precise surface finishes.
Do not remove items from the package until you are ready to use them.
Procedure
1.
2.
3.
4.
5.
6.
7.
230
Screw
10).
cell replacement cell contains an O
2
Remove the four Allen cap screws (M,
cell.
The cell flange has a knot that may be used to gently pry the flange away from the
heater tube (I).
Note
The pad on the end of the contact/thermocouple assembly (A) will sometimes fuse to the O
cell (L).
If the O cell is fused to the contact pad, push the O
2
(against spring pressure) and quickly twist the O
The cell and contact pad should separate. If the contact pad stays fused to the cell, a
new contact/thermocouple assembly must be installed.
Remove and discard the gasket (J). Clean the mating surface of the heater tube (I).
Remove burrs and raised surfaces with a block of wood and a crocus cloth.
CAUTION!
EQUIPMENT DAMAGE
Use care when handling the contact and thermocouple assembly. The ceramic rod in this
assembly is fragile.
Remove screws (B), lockwashers (C), return wire (D), and heater strut assembly (E).
If replacing contact and thermocouple assembly (A), use a pencil to mark the
location of the spring clip (H) before removing. Squeeze tabs on the spring clip to
remove. Retain the spring clip and spring (G); replace if damaged.
While carefully handling the new contact and thermocouple assembly (A), lay the
old assembly next to the new one. Transfer match marks to the new assembly.
Carefully guide the new contact and thermocouple assembly (A) through the strut
bracket (F), spring (G), and spring clip (H) until the spring clip reaches the pencil
mark.
cell until all other possibilities for poor performance have
2
cell and flange assembly, gaskets, socket head
2
Figure 9-12) from the O
cell.
2
cell replacement kit (refer to
2
cell. Remove the O
2
cell back into the heater tube
2
OCX 8800
2
2