Prior To Operation; Important; Detecting Leaks - Restek 28500 Manual De Instrucciones

5.0 Prior to Operation

Verify the operation of the leak detector before each use by sampling gas from a GC split vent or other source
of gas (other than air). Also, visually inspect the probe tip, reference gas inlet, and exhaust port for obstructions
(Figure 1).
IMPORTANT: Fittings being checked must be clean and dry; liquids, dust, and other debris may damage the leak
detector if drawn into the probe. Testing for leaks around hot fittings could increase the risk of burns. Hot fittings
may also affect the operation of the leak detector.
NOTE: The leak detector responds to almost any gas. Solvent vapors, split vent exhaust, or even strong air
currents around the probe or reference inlet can cause instability or false positive readings. Be careful not to
breathe into the reference inlet when checking for leaks, and do not cover/block the reference inlet with your
hand.
Figure 1: Leak detector schematic.

6.0 Detecting Leaks

With the leak detector turned on and zeroed, slowly move the probe tip around fittings and other potential
leak sources. If the leak detector senses a gas other than air, the LEDs will begin to light, with more lights
indicating a more significant leak. On the third red, or second yellow LED, an audible tone will begin to beep.
The more LEDs that illuminate, the faster the beep frequency. When the last red or yellow LED illuminates, the
beep becomes a steady tone. The red LEDs indicate a helium or hydrogen leak. The yellow LEDs indicate a
nitrogen, argon, or carbon dioxide leak.
Remove the probe from the vicinity of the leak and allow the unit to return to zero. If a large amount of gas
has entered the probe, it may take a few seconds for the instrument to clear that gas and reset itself. Do not
attempt to zero the unit while it is exhausting the gas from the probe. This may cause the unit to malfunc-
tion. Once reset, place the probe near the leak again to confirm its location. The reference gas inlet (Figure
1) must not be restricted or the unit will not operate correctly. Similarly, the exhaust port allows the gas
being tested to exit the leak detector and must remain unobstructed. The exhaust port is located in the
probe holder.
CAUTION: This unit should only be used to detect trace amounts of hydrogen arising from a small leak in a non-
flammable environment, e.g., laboratory room air, etc.
NOTE: To disable the audible beep during leak detection, depress and hold the zero set button for 2–3 seconds.
After you hear a steady tone for 1 second, release the button; the beep function is disabled. To turn the beep
function on again, depress and hold the zero set button. The beep function is always enabled at power-up.
NOTE: The leak detector will power down after 6 minutes of operation. This feature prevents excess battery
discharge if the unit is accidentally left on.
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