Siemens SIPROCESS GA700, Operating Instructions Manual, Page: 186 / 224

8.3.7 Checking the sample gas path for leaks
Test conditions
Observe the following conditions before commencing with the leak test.
● Check the tightness with air or nitrogen (test gas) at the operating temperature.
● The tightness is determined using the pressure drop method. The magnitude of the
pressure drop is a measure of the tightness of the gas line.
Note
Gas path volume during the leak test
The procedure described below is based on a gas path volume of 10 ml. If you select a
larger volume, you must set a correspondingly smaller value for the maximum permissible
change in pressure.
Procedure
1. Close the reference gas inlet.
2. Connect the sample gas outlet to a pressure measuring instrument.
3. Apply a pressure of approximately 1200 hPa (absolute pressure) to the sample gas inlet.
Then close the measuring gas inlet.
4. Wait for approximately 1 minute until the test gas that flowed in has reached the ambient
temperature.
5. Note the pressure.
6. Wait approximately 5 minutes. Note the pressure again.
If the pressure change is < 10 hPa, the sample gas path is adequately tight.
Commissioning
8.3 OXYMAT 7
Field device
74
Operating Instructions, 05/2015, A5E35640463-02