76
SCD and NCD User Manual
5
Maintenance
Replace the Quartz Tube (NCD)
To replace the NCD quartz tube:
1
Gather the following:
•
Two 7/16-inch open-end wrenches
•
3/8-inch open-end wrench
•
5/8-inch open-end wrench
•
New quartz tube
•
Tweezers
•
1/8-inch cap for transfer line
•
T20 Torx driver
•
Dental tool or similar tool for graphite ferrule removal
•
2 New graphite ferrules
2
Prepare the detector for maintenance.
a
Load the GC maintenance method and wait for the GC to
become ready. (See
page 69.) Wait until the inlets, oven, detectors, valve box,
burner assembly, and detector base cool to a safe handling
temperature (< 40 °C).
b
Turn off all hydrogen flows. (Leave on the oxidizer and
ozone supply gases.)
c
Turn off the ozone generator.
WARNING
The oven, inlets, and detectors can be hot enough to cause burns.
Cool these areas to a safe handling temperature before beginning.
CAUTION
Wear clean, lint-free gloves to prevent contamination of parts with
dirt and skin oils.
CAUTION
Most steps in this procedure require the use of two wrenches, one
to hold the burner steady and the other to loosen a part. Always use
two wrenches to avoid over-torquing or bending the burner
assembly.