Interpretation Of Results - RESTEK 28500 Manuel D'instructions

10.0 Interpretation of Results

Figure 4 illustrates the leak detec-
tor's LED light response range. A
greater number of lit red or yellow
LED lights correlates in general to
a larger leak.
NOTE: The leak detector is not
a quantitative device, rather it is
designed to detect leaks in gas
line connections commonly asso-
ciated with laboratory equipment.
Figure 4: LED light response chart for the leak detector. A 1:1 ratio (probe:reference) indicates no leak
present. Red LED lights indicate the presence of helium and/or hydrogen. Yellow LED lights indicate the
presence of nitrogen, argon, and/or carbon dioxide.
**CAUTION: This unit should only be used to detect trace amounts of hydrogen arising from a small leak in a nonflammable environment, e.g.,
laboratory room air, etc.
Tip drift
Tip drift is the phenomenon when a false LED light response is registered as the probe or the unit is quickly
moved. Tip drift is inherent to all dual thermistor leak detector technology and is based in large part on the
asymmetry of the flow cells; shaking or tipping the unit influences the air flow profiles, which impacts the rates
of heat exchange. If the device is functioning normally, the LED light signal will return to zero in 3–5 seconds
after the unit is held still. In extreme cases, the unit may need to be re-zeroed before using. To avoid tip drift,
be sure to hold the unit body steady while making measurements with the probe tip.
Gas
Helium
Hydrogen**
Nitrogen
Argon
Carbon dioxide
Minimum Detectable
Leak Rate (atm cc / sec)
1.0 x 10 -5
1.0 x 10 -5
1.4 x 10 -3
1.0 x 10 -4
1.0 x 10 -4
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Indicating
LED Light Color
Red
Red
Yellow
Yellow
Yellow
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