37
The Sensor ZERO Function......continued
Select the Zero function from the Engineers menu and the following screen is
displayed.
Flow zero gas and observe the reading. Once stable select the ZERO button to send
the zero command to the detector head. Observe the ZERO reading to ensure it has
returned the detector to zero reading.
0%
±
2% of Range
Select to move between
channels. Tap on the channel
number to type in the channel
number if known.
Procedure for check reaction time to gas
Ensure detector is at zero +/- 1% LEL
Use standard IGD professional gas introduction kit with 2M hose.
Connect calibration gas but do not turn on
Using a stop watch turn on the calibration gas and time to 50% and 90% LEL
Time to 50% should be less than 30 seconds
Time to 90% should be less than 60 seconds
Note on a 20% LEL bottle T50 point is 10% LEL and T90 point is 18% LEL
on a 50% LEL bottle T50 point is 25% LEL and T90 point is 45% LEL
replace non conforming sensors
