Teledyne 2240 – Portable Handheld Hydrogen Leak Detector, 3rd generation (updated 1/31/11) - Manual (Page 17)

Handheld Hydrogen Leak Detector Model 2240
Teledyne Analytical Instruments Page 17 of 30
4.5 Hydrogen-Free Areas
For the purposes of this document a hydrogen-free area is
one with less than 5ppm of hydrogen in the air.
It may be difficult to find a hydrogen-free area in a facility
where hydrogen is used. Nearby rooms, or even the entire
building, may not be hydrogen free.
To check these areas reset or zero the sensor outside,
away from any hydrogen tanks, pipes, or other potential
sources. Walk through the facility, watching the sensor. It
is surprising how far low levels of hydrogen can spread.
If the sensor is zeroed or reset in hydrogen, there will be a
negative offset in the readings that could compromise the
sensor’s ability to find small leaks.
4.6 Reset Operation
The Reset Operation is used to speed recovery from
hydrogen exposure.
It can be invoked from the keypad while in the top menu
level (measuring hydrogen) by pressing and holding
◄►(left and right arrow buttons simultaneously) or from
the Reset Menu (see Section 5). Once invoked the user is
asked to confirm the operation by pressing the ENTER
key. Pressing any other key will abort the operation.
During Reset the LCD indicates a count down to
completion and the Probe tip LED is yellow.
WARNING: The instrument must be in a hydrogen free
environment with the LCD indicating less than 0.1%
hydrogen before invoking the Reset operation.
4.7 Zero Operation
The Zero Operation is used to zero the hydrogen reading if
the instrument is reporting low levels (0.001% to 0.01%) of
hydrogen when no hydrogen is present. This operation
can be invoked from the keypad while in the top menu
level (measuring hydrogen) by pressing and holding
◄ (left
arrow button) or from the Reset Menu (see Section 5).
Once invoked the user is asked to confirm the operation by