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Model 9110T NOx Analyzer Troubleshooting & Service
Teledyne Analytical Instruments 274
2. If the actual flow is low or zero, check if the pump operates properly. The
RCEL pressure should be below 10 in-Hg-A at sea level.
If it is above 10”, rebuild the pump (Section 11.3.4.1). Check the spare parts list
in Appendix B on how to order pump rebuild kits.
3. Check if the particle filter is clogged.
Briefly remove the particle filter to see if this improves the flow.
Be very cautious when handling the Perma Pure dryer fittings (see Section
11.3.2 on proper handling instructions).
If the filter is clogged, replace it with a new unit.
If taking off this filter does not solve the problem, continue to the next step.
Do not leave the Perma Pure dryer without filter for more than a few seconds,
as you may draw in dust, which will reduce the performance of the dryer.
4. A leak between the flow meter and the reaction cell (where the flow-
determining critical orifice is located) may cause a low flow (the system
draws in ambient air through a leak after the flow meter).
Check for leaks as described in Section 11.3.12.
Repair the leaking fitting, line or valve and re-check.
5. The most likely cause for zero or low ozone flow is a clogged critical flow
orifice or sintered filter within the orifice assembly.
The orifice that sets the ozone flow is located on the reaction cell.
Check the actual ozone flow by disconnecting the tube from the reaction cell
and measuring the flow going into the cell.
If this flow is correct (~80 cm³/min), the orifice works properly.
If this flow is low, replace the sintered filter.
The orifice holder assembly allows a quick and easy replacement of the filter
(see Section 11.3.5 and on for replacement procedures).
Appendix B lists a spare part kit with a complete orifice assembly that allows a
quick replacement with minimum instrument down-time.
12.4.1.3. High Flow
Flows that are significantly higher than the allowed operating range (typically ±10-11% of the nominal
flow) should not occur in the 9110T unless a pressurized sample, zero or span gas is supplied to the inlet
ports.
Ensure to vent excess pressure and flow just before the analyzer inlet ports.