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Teledyne API Model M201E NH
3
Analyzer Operator Manual Maintenance Schedule
05206H DCN5910 39
4.4 AUTOZERO FLOW CHECK
Since the M201E is an ammonia analyzer, the flow through the AutoZero orifice is
especially important. Check the AutoZero flow as follows:
1. This procedure should be performed with the sample pump running.
2. Remove the top cover of the analyzer. Locate the vacuum manifold at the
center rear of the chassis. Locate the 1/8” tube fitting located on the very left
side, as viewed from the rear of the analyzer. It will have a label of “0.010”
indicating the flow orifice installed.
3. Remove the fitting and attach a calibrated flowmeter to the block fitting capable
of measuring in the range of 500 cc/min. The flowmeter should indicate a flow
of 500 cc/min 10%.
4. If the flow is outside this range (most likely lower, due to plugging):
1. Turn off the sample pump and instrument.
2. Remove the 1/8” pipe-to-tube fitting and remove the ¼” sintered filter (p/n
FL0000001). This filter is meant to protect the orifice; it will usually
become plugged and need replacement rather than the orifice. Replace
the filter, and then re-assemble the manifold. Restart the sample pump
and recheck the flow.
Table 4-3. Analyzer Flow Check
M501 NH
3
, Converter sample flow check
Note: Connect both the Teflon
tubes between analyzer and converter
GAS PORT Expected Flow (cc/min)
“Sample In” 1000 +/- 10 %
Analyzer sample flow check
Note: Disconnect both the Teflon
tubes between analyzer and converter
GAS PORT Expected Flow (cc/min)
“To Conv”
0
1000 or 500, +/- 10 % When the analyzer is sampling
TNx only, the bypass flow is
measured. Therefore, the flow
alternates between 500 and
1000 cc/min. This is the NOx
channel.
“From Conv” 500 +/- 10% This is the TNx channel.