63
5 Maintenance
5.2.2
Test gases for the adjustment
The following test gases can be used for adjustment:
Gas
Suitable test gases for
Zero point
Sensitivity
CH
4
●
Fresh air
●
Gas mixture
●
10 ppm CH
4
*)
●
100 ppm CH
4
*)
●
1000 ppm CH
4
*)
●
1.0 % vol. CH
4
*)
●
2.2 % vol. CH
4
*)
●
100 % vol. CH
4
C
3
H
8
●
Fresh air
●
1 % vol. C
3
H
8
*)
●
100 % vol. C
3
H
8
C
4
H
10
●
Fresh air
●
1 % vol. C
4
H
10
CO
●
Fresh air
●
Gas mixture
●
40 ppm CO
CO
2
●
Fresh air
●
Gas mixture
●
2.0 % vol. CO
2
●
20 % vol. CO
2
H
2
S
●
Fresh air
●
Gas mixture
●
40 ppm H
2
S
O
2
●
Gas mixture
(free from O
2
)
●
100 % vol. CH
4
●
Fresh air
*)
in synthetic air
If more than one test gas can be used to adjust a gas, it does not
have to be adjusted with all test gases. However, adjusting with
more than one test gas increases the measurement quality.
Every gas must be adjusted separately, Except for adjustment
with a gas mixture (see section 5.2.3
).
Fresh air contains 20.9 % vol. O
2
and is therefore used with ox-
ygen to adjust the sensitivity.
Propane C
3
H
8
and butane C
4
H
10
can only be adjusted with indi-
vidual gas.