Varian 450-GC, User Manual

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Flame Ionization Detector (FID) - Detectors
Varian, Inc. User Manual 450-GC Page: 289
Disassemble the FID
To disassemble the FID, proceed as follows:
1. Set the FID to 50 °C and wait for it to cool before disassembly. Turn the
detector electronics and detector oven OFF in the active method. Remove
the GC Top-Covers.
2. Turn off the main GC gas supplies to the detector at the pneumatics panel.
These are the make-up, hydrogen and air supplies.
3. Disconnect the signal and igniter cables from their probes on the detector
tower.
4. Remove the signal and igniter probes from the detector tower. DO NOT
rotate the probes as you disconnect them from the electrical contacts in the
tower. Place the probes on a clean surface such as a lint-free laboratory
tissue.
5. Remove the 2 tower mounting screws from the top of detector tower.
6. Remove the tower assembly from the detector oven, lifting straight up until
clear of the flame tip. Remove the collector tube and insulator from the
detector tower. Avoid contamination of the ceramic insulator and probes. If
the detector is not completely cool, use a metal tool (such as tweezers or a
hooked wire) to remove parts from the tower assembly. Place parts on a
clean Kimwipe®. Never place them on a counter or painted surface.
7. Remove the flame-tip assembly from the detector base. Take care not to
break the ceramic flame tip tube or the Vespel®/graphite or graphite ferrule.
8. Remove and discard the aluminum seal washer from the detector base.
Always use a new aluminum seal washer each time you reassemble the
detector. Note that the aluminum seal washer may remain in the detector
tower when the tower is removed from the base.