Figure 9-3. Flow Diagram, Lag Volume - Thermo Scientific 42i Instruction Manual

Optional Equipment
Ammonia Scrubber
Lag Volume Test
Ammonia Scrubber
Teflon Particulate
9-12 Model 42i Instruction Manual
Figure 9–3. Flow Diagram, Lag Volume
Use the following procedure to test the Model 42i with lag volume option.
1. Set the NO range to 1,000 ppb and the averaging time to 10 seconds.
2. Introduce approximately 800 ppb NO into the Model 42i. Wait for a
stable reading and then record the NO
air into the Model 42i. Wait until the instrument reads close to zero
(<3 ppb). Repeat the above procedure two more times. Take the
average of the three NO
less than 50 ppb.
The ammonia scrubber is mounted internally and removes ammonia from
the sample air.
A 5-10 micron pore size, two-inch diameter Teflon® element is available for
the Model 42i. This filter should be installed just prior to the
Filter
bulkhead. When using a filter, all calibrations and span checks must be
performed through the filter.
reading. Next, introduce zero
2
readings. The average NO
2
reading should be
2
SAMPLE
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