Cell Replacement - Emerson Rosemount 6888A Reference Manual

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5.4.5

Cell replacement

This section covers oxygen sensing cell replacement. Do not attempt to replace the cell
until all other possibilities for poor performance have been considered.
If cell replacement is needed, order the cell replacement kit
The cell replacement kit
setscrews, socket head cap screws, and anti-seize compound. The items are carefully
packaged to preserve precise surface finishes. Do not remove items from the packaging
until they are ready to be used. Spanner wrenches and hex wrenches needed for this
procedure are part of an available special tools kit
WARNING!
BURNS
Use heat-resistant gloves and clothing when removing the probe. Do not attempt to work on
these components until they have cooled to room temperature. Probe components can be as
hot as 300 °C (572 °F). This can cause severe burns.
Disconnect and lock out power before working on any electrical components. There is voltage
up to 240 Vac.
Reference Manual
When replacing the strut, orient the probe so that the small calibration gas tube is at
the 6 o'clock position of the probe tube. Align the slot on the heater plate with the
calibration gas line in the probe tube. Slide the strut into the probe tube.
It turns to align the hole on the back plate of the strut with the calibration gas line.
When the hole and calibration gas line are aligned correctly, the strut slides in the
rest of the way.
As the strut insertion nears completion, install the guide rod into the calibration gas
tube to assist in guiding the calibration gas tube through the hole in the end of the
strut.
Replace the CAL and REF gas Viton tubes (K).
Insert the strut clamp (H) back into the finned housing on the probe.
The opening should be down to allow for clearance for the gas tubes.
Carefully install the O-ring (I) back into the groove between the two housings.
A small amount of silicone grease may be used to hold the O-ring in place. Do not
use petroleum based grease.
Insert the strut wire harnesses into the housing.
Turn the conduit ports of the housing to the CAL and REF gas ports side of the probe
and position the housing on the probe.
Install and tighten the four screws (J).
Follow the instructions in
Follow the instructions in
duct.
(Figure
Section 5.4.2 to install the electronics into the housing.
Section 5.4.1 to install the transmitter into the stack or
5-4) contains a cell and flange assembly, corrugated seal,
(Table
Maintenance and service
(Table 6-1).
6-1).
105