INFICON Sensistor ISH2000 Hydrogen Leak Detector - Manual (Page 76)

Sensistor ISH2000 Technical Reference Manual (TRM) EN- 76
D 300
D 300 Reference leak trouble guide
It is very important that we advice the end user to carefully study the manuals
for how to take best care and handle the reference leaks.
Here are a couple of mistakes a user can make:
1 The small leaks with a gas container (E, F and G) are delivered at atmospheric
pressure due to transportation limitations. This means that the end user has to
start by filling the gas container to the indicated pressure. This filling MUST be
conducted according to the included instructions to ensure you get as close as
possible to a 5%H2/95%N2 gas mix inside the container. Otherwise you risk
having an undefined gas mix in the container, and what is on the certificate is in
that case no longer valid.
2 The smaller leaks that have a gas container are sometimes emptied by the
new user, simply because he sees the fill valve and "have to try what it is for".
This way you empty the container quite effectively. After this you need to refill
the container. See above in point 1 for possible problems.
3 When users connect leak A, B, C to the gas line they sometimes forget that
the hose from the bottle may be full of air to start with. If they do this the leak
will appear to be very difficult or impossible to pick up by the detector simply
because there is mainly air passing through the leak to start with. What they
should do is purge the hose from air before attaching it to the leak. Also
remember to use the purge valve on the leak itself to release any air trapped
inside the leak housing, and replace it with tracer gas.