AC 7490
ELECTRONIC LEAK DETECTOR FOR NITRO-TRACE TESTING (N2-H2)
IMPORTANT: Make sure sensor is fully inserted for proper operation. The detector will stay in warm-up mode and
the on/off switch will become inoperative if the sensor becomes loose or is not fully inserted.
Control panel
1.TURN ON: Press the ON/OFF button once to turn on and again to turn off. NOTE: Hold button down for
approximately 1 second to turn unit off
2. WARM UP: The detector automatically starts heating the sensor. During the heating cycle, the digital indicator
will fl ash O and the detector will sound a slow «beep». Warm up is usually less than 20 seconds.
3. READY: The detector is ready to begin searching for leaks when the fl ashing 8 stops and the green sensitivity
LED turns on. The audio «beep» increases in frequency and probe LED begins to blink steadily.
4. SEARCHING: When searching for leaks, move the sensor tip along ale lines and fi ttings no further away than
9.5mm and no faster than 75 mm/sec. If the detector alarms, make smaller sweeps back and forth until the leak
source can be pin pointed.
Note: The D640 on/y responds to changes in leak concentration. The a/arm wi/1 re-set automatically if the
sensor tip is held at the leak source.
Digital display
The digital leak size indicator remains off normally but once a leak is detected, a number from 1-9 will be displayed
for all H2 tracer gas regardless of the sensitivity setting.
The number will continue to increase or decrease depending on the amount of tracer gas sensed. The maximum
Digital display
Low battery indicator
Sensitivity level
Mute mode & sensitivity level
Power on/off
