TESTO 335 Instruction Manual page 34

F. Configuration
34
F.2 Sensor settings
Recalibration:
CO, SO2, NO2, NO measuring cells and the O2 reference value can be recalibrated.
Measurement gas dilution in slot 2 can be recalibrated.
If obviously unrealistic readings are displayed, the measuring cells should be checked
and recalibrated as required.
Dangerous gases
Danger o o f p p oisoning!
Observe safety regulations/accident prevention regulations when handling
test gases.
Use test gases in well ventilated rooms only.
Recalibration with low gas concentrations can lead to deviations in accuracy in the
upper measuring ranges.
Sensor protection is not deactivated during recalibration. For this reason, test gas
concentration should be lower than the threshold values set for sensor protection.
Recalibrating the measuring cell at slot 2 has an effect on the dilution:Always carry
out a recalibration of measurement parameters before a recalibration of dilution.
The following conditions must be met when recalibrating:
· Use absorption-free tube material
· Switch the measuring instrument on at least 20 min before recalibration (warming-up)
· Use clean air for gas zeroing
· Charge the test gas via calibration adapter (0554 1205, recommended) or the tip of
the probe
· Maximum overpressure of the test gas: 30 hPa (recommended: unpressurised via
bypass)
· Charge the test gas for at least 3 min
Recommended test gas concentrations and compositions are given in Testo's field
guide to test gases.
1
Recalibration
- Possibly:Gas zeroing (30 s).
2 Select the parameter
3 Charge the measuring cell with test gas.
.
OK
Change
Enter the test gas concentration (nominal value).