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Teledyne API - Model 200EH/EM Operation Manual Instrument Maintenance
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7. Do not remove the sample and ozone nozzles. They are Teflon threaded and require a special tool for
reassembly. If necessary, the manifold with nozzles attached can be cleaned in an ultrasonic bath.
8. Reassemble in proper order and re-attach the reaction cell to the sensor housing. Reconnect
pneumatics and heater connections, then re-attach the pneumatic sensor assembly and the cleaning
procedure is complete.
9. After cleaning the reaction cell, it is also recommended to exchange the ozone supply air filter chemical
10. After cleaning, the analyzer span response may drop 10 - 15% in the first 10 days as the reaction cell
window conditions. This is normal and does not require another cleaning.
9.3.8. CHANGING CRITICAL FLOW ORIFICES
There are several critical flow orifices installed in the M200EH/EM, Figure 9-5 shows one of the two most
important orifice assemblies, located on the reaction cell. Refer to Section 10.3.3 for a detailed description on
functionality and locations. Despite the fact that these flow restrictors are protected by sintered stainless steel
filters, they can, on occasion, clog up, particularly if the instrument is operated without sample filter or in an
environment with very fine, sub-micron particle-size dust.
The M200EH/EM introduces an orifice holder that makes changing the orifice very easy. In fact, it is
recommended to keep spare orifice holder assemblies at hand to minimize downtime and swap orifices in a
matter of a few minutes. Appendix B lists several complete spare part kits for this purpose.
To replace a critical flow orifice, do the following:
1. Turn off power to the instrument and vacuum pump. Remove the analyzer cover and locate the reaction
cell (Figure 9-5, Figure 11- and Figure 3-4).
2.
Unscrew the 1/8” sample and ozone air tubes from the reaction cell
3. For orifices on the reaction cell (Figure 9-5): Unscrew the orifice holder with a 9/16” wrench. This part
hold
s all components of the critical flow assembly as shown in
Figure 9-6. Appendix B contains a list of spare part numbers.
4.
For orifices in the vacuum manifold: the assembly is similar to the one shown in
Figure 9-6, but without the orifice holder, part number 04090, and bottom O-ring OR34 and with an NPT
fitting in place of the FT 10 fitting. After taking off the connecting tube, unscrew the NPT fitting.
04521C (DCN5731)