Installing the Gas Analyzer  73 
 
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 
synthetic 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 
recommended 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 129) (and the continuous housing purge 
therefo
re fails). 
9  Connect (see page 66) the combustion gas line to the combustion 
gas inl
et 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 116) the seal integrity of the combustion gas line 
af
ter connection.