Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 215)

Instrument Maintenance Model 9110TH NOx Analyzer
Teledyne Analytical Instruments 195
6.4.4. CHANGING THE NO
2
CONVERTER
The NO
2
converter is located in the center of the instrument, see Figure 3-5 for location,
and Figure 6-3 for the assembly. The converter is designed for replacement of the
cartridge only, the heater with built-in thermocouple can be reused.
1. Turn off the analyzer power, remove the cover and allow the converter to cool.
2. Remove the top lid of the converter as well as the top layers of the insulation until
the converter cartridge can be seen.
CAUTION
THE CONVERTER OPERATES AT 315º C. SEVERE BURNS CAN RESULT IF THE
ASSEMBLY IS NOT ALLOWED TO COOL. DO NOT HANDLE THE ASSEMBLY UNTIL
IT IS AT ROOM TEMPERATURE. THIS MAY TAKE SEVERAL HOURS.
3. Remove the tube fittings from the converter.
4. Disconnect the power and the thermocouple of the converter. Unscrew the
grounding clamp of the power leads with a Phillips-head screw driver.
5. Remove the converter assembly (cartridge and band heater) from the can. Make a
of the orientation of the tubes relative to the heater cartridge.
6. Unscrew the band heater and loosen it, take out the old converter cartridge.
Figure 6-3: NO
2
Converter Assembly
7. Wrap the band heater around the new replacement cartridge and tighten the screws
using a high-temperature anti-seize agent such as copper paste. Make sure to use
proper alignment of the heater with respect to the converter tubes.
8. Replace the converter assembly, route the cables through the holes in the can and
reconnect them properly. Reconnect the grounding clamp around the heater leads
for safe operation.