Crowcon Tetra MO7237, User Manual, Page: 24 / 36

6.4 Cal/Test
This can arise if having selected and confirmed calibration one or more (but not
all) of the sensors are not calibrate enabled. In this case calibrate enabled chan-
nels will calibrate, and non-enabled channels will Gas Test (bump) only.
Oxygen i-modules are usually not set to calibrate enabled as the calibration at
20.9% on atmospheric air during the zero process is more accurate and repeat-
able than using certified gas mixtures. Provided it completes a successful test
and the other i-modules fitted successfully calibrate the calibration due date for
oxygen will be reset during a Cal/Test.
6.5 Gas test/calibration troubleshooting
Symptom Possible Cause Action
No response to gas Gas cylinder empty Check gauge, replace cylinder
as needed
Hose blocked or kinked Ensure no restriction to flow
Tetra fails gas test Gas cylinder empty Check gauge, replace cylinder
as needed
Gas cylinder out of date Check date and replace as
needed
Hose blocked or kinked Ensure no restriction to flow
Calibration drifted Calibrate Tetra
Gas flow not started imme-
diately
Repeat test, starting gas
immediately
Tetra fails calibration Gas cylinder empty Check gauge replace bottle as
needed
Gas cylinder out of date Check date and replace as
needed
Hose blocked or kinked Ensure no restriction to flow
Calibration drifted Calibrate Tetra
Stabilisation time too short Reset using PC software
Tetra passes gas test
but will not enter
calibration mode
Menu Zero not performed
Tetra not field calibration
version
Select Zero from menu
Send for re-configuration
Note:
Remove regulator from gas cylinder when not in use over a prolonged
period.
For parts list, see section
XI .
0
Gas test/calibration troubleshooting Tetra