100  AO2000 CONTINUOUS GAS ANALYZERS  |  OI/AO2000-EN REV. B 
 
 
 
Fidas24: Connecting the combustion gas line 
Connecting the combustion gas line 
Cleaning the combustion gas line   
1  Pump cleaning agent (alkaline cleaner, stainless steel pickling agent) 
through the stainless steel tube. 
2  Thoroughly rinse the tube with distilled water. 
3  Purge the tube for several hours at a temperature of > 100 °C with syn-
thetic air or with nitrogen (10 to 20 l/h). 
4  Seal the ends of the tube. 
Connecting the combustion gas line   
5  Connect a two-stage cylinder pressure reducer (version for high purity 
gases) to the combustion gas cylinder. 
6  Connect the combustion gas line to the cylinder pressure reducer. 
7  Install a flow restrictor in the combustion gas supply line which restricts 
the combustion gas flow to 10 l/h of H
2
 or 25 l/h of H
2
/He mixture. This 
means that operation of the gas analyzer is safe even with a defect in 
the combustion gas feed path (e.g. leaks). 
8  Install a shut-off valve in the combustion gas supply line. It is recom-
mended that a pneumatic valve is installed; this valve must be controlled 
by the instrument air supply in such a way that the combustion gas feed 
is automatically shut off if the instrument air supply fails (see page 335) 
(and the continuous housing purge therefore fails). 
9  Connect (see page 83) the combustion gas line to the combustion gas 
inlet of the analyzer module via a pressure regulator (0 to 1.6 bar). 
Check the seal integrity of the combustion gas line 
10  Check (see page 283) the seal integrity of the combustion gas line after 
connection.