INFICON Sensistor ISH2000 HySpeed Hydrogen Leak Detector - Manual (Page 24)

Hydrogen leak detector Sensistor ISH2000 HySpeed - Operating Instructions
24 OP-Sensistor ISH2000 HySpeed-EN-201203
EN
To set up:
The operation in Detection Mode is not quantitative. No figures are given but the
signal is still increasing and decreasing with gas concentration. Therefore, there is
no actual calibration to be done, but rather a setting of the sensitivity to a desired
level.
A typical set-up procedure for the Detection Mode is:
•
Set up a reference leak which corresponds to the smallest leak you wish to
detect.
• Put the probe close to the reference leak and note approximately what reaction
you get (no reaction, small, medium, high, full scale) within the first few
seconds.
• Set the sensitivity. This can be done permanently under the menu Detection Mode
or temporarily as a Direct Sensitivity Setting on the display (unless you have set
this function to OFF under menu Sensitivity Settings. There is also an Auto
ranging function which can be selected under the
Detection Mode Settings
menu.)
If the sensitivity is set very high, you may find the baseline annoyingly unsteady.
Note: If the Detection Mode is used and the alarm function is required to be
activated at a particular calibrated level, then the unit must be calibrated. The
reason for this is that the alarm is immediately based on the Analysis Mode
when the Detection Mode is displayed, due to inaccuracies in the Detection
Mode signal.
To locate leaks
Detection mode is semi-quantitative, that is, it gives an audio and visual signal
which increases as a leak is approached (a higher gas concentration) and decreases
as you move the probe away from the leak. It does not display figures.
In this mode of operation leaks can easily be detected using a sensitivity which can
be preset. Leaks can be located very accurately, even when there are other leaks
nearby.
If, for example, you are trying to locate a leak on a refrigerator condenser tubing
and the tubing has a major leak, then you will get an audio signal as soon as the
probe is placed close to the condenser tubing. When the probe is moved around
over the condenser, the signal will increase as the probe approaches the leak. If the
signal goes off the scale, simply reduce the sensitivity setting to bring the signal
within the scale. By working with the sensitivity setting in this way, you will be able
to locate multiple leaks that are in close proximity to each other.
Do not expose the probe to more gas than is necessary, because it will slowly
saturate with time. It is good practice to detect a leak, locate it, and immediately
remove the probe to avoid saturation. The probe is not damaged by the exposure
but it will recover more slowly. After excessive exposure it will be less sensitive for a
short period of time.
Background compensation
There is always some hydrogen gas in the background. In fresh air this is as low as
0.5 ppm (parts per million).
Sensistor ISH2000 HySpeed actively adjusts itself to the background.
Sensitivity
Sensitivity of audio signal and signal bar in Detection Mode .