When using the GA machines for sub surface gas analysis there can in certain circumstances be inadequate flow from the monitoring point to meet the suction demands of the analyser pump. This results in a Flow Fail condition in the analyser and no result can be obtained. Conditions leading to this result include blockage of the sample point at depth and water in the sampler.
The GA5000 analyser has a setting that allows the adjustment of the flow fail sensitivity. This setting should be altered when a flow fail condition is encountered.
NOTE: The low sensitivity flow fail setting must only be used when a Flow Fail is encountered, and MUST NOT be used for normal operation
To adjust the sensitivity please follow the instructions below:
Once the machine is turned on and in the normal operating mode, and after a FLOW Fail has been encountered, press the MENU button on the analyser. This displays the screen shown below
Select the Adjust Flow Fail icon. This displays the Flow Fail Sensitivity window as shown below:
Adjust the setting to the lowest setting and select EXIT on each screen to return to the normal operating window.
Try to get a gas reading on the sample point again, taking care to watch for water/moisture being drawn into the analyser. If water/moisture are spotted immediately pull of the analyser tube and switch of the pump.
If there is still a flow fail, record this. If a reading is obtained store the reading in the usual way.
NOTE: Once the testing of the monitoring point experiencing the Flow Fail has been completed ENSURE YOU RETURN THE SENSITIVITY SETTINGS TO NORMAL following the sequence above.