Teledyne API Model 200A NOX Analyzer Instruction Manual, 02246, Rev. G, DCN 5247
8.9 Leak Check Procedure
If a leak checker is not available, it is possible to leak check the instrument using the M200A's
pump plus a shut-off valve.
1. Turn off instrument power and pump power.
2. Cap the sample inlet port, ozone generator air inlet, and zero air inlet (if IZS option
present).
3. Insert a shut-off valve between the sample pump and the vacuum manifold at the rear of
the instrument.
4. Turn on the sample pump and set the TEST function to RCEL, which measures the
reaction cell pressure. Close the shutoff valve and monitor the cell pressure. The pressure
should not drop more than 1"Hg(.5psi) in 5 minutes. If there is a leak, it is not possible by
this method to tell where it is located. You can locate the leak by using a pressure leak
checker described below.
5. The sensor module is equipped with a fitting at the top of housing near the heat sink fins.
This fitting can be pressurized and the sensor checked for leaks. The leakdown rate is the
same as above.
If you have a leak checker:
1. Turn off instrument power and pump power.
2. Disconnect pump at rear panel. Cap the sample inlet port, ozone generator air inlet, and
zero air inlet (if IZS option present) and connect the leak checker to the exhaust port.
CAUTION
Pressure must be less than 15 psi.
3. Pressurize system and check for leaks by watching overall pressure. The pressure should
not drop more than 2"Hg(1 psi) in 5 minutes.
If the instrument fails the pressure test, each fitting needs to be leak checked to find the location.
Be careful that the system is always pressurized so as not to draw soap solution into the
plumbing system. Make sure you dry off any accumulated bubble solution. Refer to Table 8-8-6,
Table 8-8-7, Table 8-8-8 for pneumatic diagrams.
The Sensor module can be leak checked as a unit using a 1/8" tubing fitting on top of the
assembly. The same rules as above apply.
1. Pressurize to <15 psi.
2. After turning off pressure tester, pressure should not drop more than 2" Hg in 5 minutes.
NOTE
If the black PMT cover for the Sensor Assembly is removed, ensure to
replace the 5 dessicant bags inside the housing.
8-15
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