ACOEM Met One Instruments GAS-1060, User Manual

Page: 106 / 164

Serinus 60 User Manual 3.0
Page 106
6.3 Maintenance Procedures
6.3.1 Background Scrubber DAU check
The internal background scrubber Disposable Absorbent Unit (DAU) removes pollutants from the
sample stream providing a source of continuous NO
2
free air for background and internal zero
functions. Failure of the absorbent can result in drift, poor sensitivity near zero and high background
readings.
Note: Ensure that the instrument has been running for at least one hour before this procedure is
performed.
Equipment Required

Span gas source 400ppb NO
2

5/8” Spanner
Procedure
1. Open - Main Menu

Calibration Menu .
2. Select - Cal. Type

Manual - Accept.
3. Select - Zero Source

Internal - Accept.
4. Select - Cal. Mode

Zero - Accept.
5. Allow the instrument to sample Zero air for approximately five minutes.
6. Record the instrument response as the “Initial” value.
Note: This value should be 0.00

1 ppb. If it is not, a background should be initiated by selecting
Manual Background from within the Calibration menu . The background will take approximately five
minutes to complete (refer to Section 3.4.10).
7. Connect 400 ppb NO
2
span source to the Sample Port ensuring the inlet pressure is maintained at
ambient (vented).
8. Allow the instrument to sample the span source for five minutes.
9. Record the instrument response as the “Challenge” value.
10. Disconnect the span source.
11. Open - Main Menu

Calibration Menu .
12. Select - Cal. Mode

Measure - Accept.
13. Select - Zero Source

External - Accept.
14. Compare the “Initial” value and the “Challenge” value. They should agree within

2 ppb
otherwise replace the background scrubber DAU.