Tube Replacement for the NCD
The Burner has one quartz combustion tube that requires replacement. Generally the tube should be replaced only if sensitivity decreases. The “Troubleshooting” chapter provides additional information to assist in determining whether tube replacement may be necessary. Refer to Figure 2 on page 46 for proper part nomenclature. Follow the instructions below for tube replacement.
1Turn off power to the GC and the Controller and let the system cool down under vacuum.
2Turn off power to the vacuum pump.
3Lift the Burner out of the shroud. It is recommended to remove the coil, noting the position of the ferrule. In some instances, if the coil can be uncoiled, it may be convenient to leave it attached to the Burner.
4Disconnect the hydrogen and oxidant lines.
5Disconnect the power connector that leads to the GC, if necessary.
6Loosen and disconnect the union fitting from the top of the Burner.
7Remove the tapered union fitting from the bottom of the Burner.
8Slide the large quartz tube out of the Burner and remove it from the quartz heater assembly.
9Insert the new quartz tube into the quartz heater assembly. Position a 1/4" ferrule (flat end butted up against the top of the swivel nut) onto the quartz combustion tube. With the ferrule positioned against the swivel nut, approximately 0.5 cm of the quartz tube should extend outside the nut.
Figure 43 Proper Ferrule Orientation to the Large Quartz Tube
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