11/11
Edition 03 - May 97
Alcatel Vacuum Technology France - ASM 180 TD/TD+ - ASM 181 TD+ User’s Manual
C 70
In the event of problems when using
the "I" gas line test option
S
YMPTOM
C
AUSE
R
EMEDY
Inject the carrier gas (40 SCCM)
and test the installation (
page 10
).
The leaks at the connections or the
line are displayed on the GL
measurement scale if the detector
is in GL mode, or Inlet Pressure
display if the detector is in
roughing mode.
• Vary the carrier gas flow while
remaining in FL mode.
If the helium signal rises with the
carrier gas flow, the carrier gas
contains helium.
• Purge the carrier gas injection
system again to remove any pos-
sible trace of residual air.
If the problem persists, the test can
be performed in the background
noise limit or change the carrier
gas.
Vary the carrier gas flow while
remaining in FL mode.
If the helium signal rises or remains
practically constant when the car-
rier gas flow falls, there is a gross
leak on the installation..
Test the installation (
page 10
).
Gross Leak on
installation
NO
The detector does not
switch to Fine Leak
mode
for example,
after 5 min
for a 1/4" line,
length
≤
100 m
The helium background
noise does not
decrease
for example, the helium
signal remains at the
10
-7
scale
(The minimum detectable leak is
limited to the value of the
helium background noise.)
The carrier gas
contains a significant helium
concentration
Gross Leak on
installation