Bake Out And Run Checkout Test; Replacing The Heater/Sensor Assemblies - Agilent Technologies 7820A Service Manual

Agilent 7820 GC Service
119
Loosen the one screw holding the adjacent cover and pivot the
cover up and off.
The FPD is now ready for replacement, if required.
If not, reassembly is the reverse of these steps.

Bake out and run checkout test

This part of the procedure bakes out the detector and restores
conditions. The detector output will level off in about 1 hour after
you restore the conditions. The detector output will continue to
drift down slowly for about 24 hours.
1 Reinstall the column or columns.
Reinstall the drain tube to the FPD exhaust tube.
Restore the gases to the GC.
Restore the power to the GC.
Restore the conditions to the inlets and detectors, but turn off the
flame of the FPD to prevent condensation.
After the FPD is at temperature for about 10 minutes, light the
flame.
Bake out the detector. Set the oven and detector temperatures to
250°C for 15 minutes. Insure there is adequate gas flows through
the column.
After the bakeout, restore the oven and FPD conditions.
Allow the output to level off.
Run a checkout and compare the results.

Replacing the heater/sensor assemblies

Replacing the heater/sensor assemblies takes about 30 minutes.
It requires you to turn off the GC, remove the vent, and the
detector cover.
When turning the GC off, turn off the flame first
to prevent condensation from dripping into the jet
and column.
You may wish to replace or check the FPD heater/sensor
assemblies for the following reasons: