Emerson Rosemount 6888C Instruction Manual page 73

Instruction Manual
00809-0100-4891
1. Follow the instructions in
transmitter from the stack or duct.
2. If the probe uses the standard diffusion element, use a wrench to remove the diffuser
assembly.
3. If equipped with the optional ceramic diffusion assembly, remove and discard the
setscrews and remove the vee deflector. Use spanner wrenches from the probe
disassembly kit
the diffusion element. If damaged, replace the element.
4. Loosen the four socket head cap screws from the cell and flange assembly and remove
the assembly and the corrugated seal.
The cell flange has a notch that may be used to gently pry the flange away from the
probe. The contact pad inside of the probe sometimes fuses to the oxygen sensing cell.
If the cell is fused to the contact pad, push the cell assembly back into the probe
(against spring pressure) and quickly twist the cell assembly. The cell and contact pad
should separate. If the contact pad stays fused to the cell, a new contact/thermocouple
assembly must be installed. Disconnect the cell and the thermocouple wires at the
crimp connections and withdraw the cell with the wires still attached.
5. If the contact assembly is damaged, replace the strut or contact pad. Follow the
instructions in
electronics housing and then follow the instructions for replacing the contact pad
provided in the cell replacement kit.
6. Remove and discard the corrugated seal. Clean the mating faces of the probe tube and
retainer. Remove burrs and raised surfaces with a block of wood and crocus cloth.
Clean the threads on the retainer and hub.
7. Rub a small amount of anti-seize compound on both sides of the new corrugated seal.
8. Assemble the cell and flange assembly, corrugated seal, and probe tube. Make sure the
calibration tube lines up with the calibration gas passage in each component. Apply a
small amount of anti-seize compound to the screw threads and use the screws to
secure assembly. Torque to 60 in.-lb (6.8 N m).
9. Follow the instructions in
reassemble the electronics housing.
10.Apply anti-seize compound to the threads of the cell assembly, hub, and setscrews.
Reinstall the hub on the cell assembly. Using pin spanner wrenches, torque to 10 ft-lb
(14 N m). If applicable, reinstall the vee deflector, orienting apex toward gas flow.
Secure with setscrews and anti-seize compound. Torque to 25 in-lb (2.8 N m).
11.On systems equipped with an abrasive shield, install the dust gaskets with joints 180 °
apart.
12.Follow the instructions in
transmitter to the stack or duct.
13.Turn on power and monitor thermocouple output.
It should stabilize at 29.3 ±0.2 mV. Set reference air flow at 1 l/min (2 scfh). After the
transmitter stabilizes, calibrate the probe. If new components have been installed,
repeat calibration after 24 hours of operation.
Instruction Manual
Remove and replace probe
(Table 9-1 on page 79) to turn the hub free from the retainer. Inspect
Heater strut replacement
Heater strut replacement
Remove and replace probe
Maintenance and service
on page 64 to remove the
on page 69, steps 2 through 4, to remove the
on page 69, steps 9 through 15, to
on page 64 to install the
July 2018
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