OPERATING INSTRUCTIONS
4
Automatic Calibration
The leak detector models covered by this manual are all equipped with spe-
cial automatic circuitry. A good understanding of how this circuitry works will
enable you to take full advantage of this feature and avoid misuse.
The automatic calibration feature works like this: Whatever level of gas sur-
rounds the tip when the unit is turned on, or reset, is taken as zero. Only a
greater concentration of gas will be indicated. If there is no gas around the tip
when the unit is turned on, or reset, the unit is set at its maximum sensitivity
and will indicate the presence of any halogen. However, if, for example, there
is a 100 ppm concentration around the tip at turn on, or reset, only a concen-
tration above 100 ppm will be indicated.
The units may be further "reset" or automatically 're-calibrated', to ambient
concentrations at any point. If an alarm occurs before a leak is pinpointed, the
units can be reset, or re-calibrated', to ignore this level; allowing you to
approach the source of the leak (which creates a larger concentration) more
closely. Follow the instructions in the Operating Tips section on page 6 to
reset, or re-calibrate, your particular model.
The automatic calibration feature makes it possible for you to ignore ambient
concentrations of gas and pinpoint leaks much more easily. For best results
turn the unit on in fresh air and then move towards the suspected leak area.
Reset as often as necessary to pinpoint the exact location of the leak.
NOTE: Because of this automatic feature, if the probe is placed in front of an
open refrigerant cylinder, and the unit is switched on, a leak may NOT be indi-
cated. This occurs because the level at the tip, at turn on, is taken as zero;
only a concentration above the level at the cylinder would be indicated.
FOR MODEL 5750A ONLY:
Model 5750A Halogen Leak Detector offers a unique Scan mode feature in
addition to the NORMAL (ON) operation mode. By using the Scan Mode a
system can be checked for leaks with a few quick passes of the probe.
Scanning will show where a region of the system is leaking. The exact leak
point can then be located by switching to the NORMAL (ON) mode of opera-
tion. This "double-barreled" approach to leak finding is an enormous time
saver.
How to Use the Scan Mode:
Switch on the unit to the Scan Mode by moving the Power Switch to the left.
The beeping rate (in fresh air) will quicken compared to the NORMAL (ON)
mode as the instrument automatically adjusts for supersensitivity. When in the
scan mode always move the probe in a constant motion
over the suspected area, keeping the probe conveniently close to the pipe,
joint etc.... Two to three inches per second is a suitable scan rate.
