Tracer Gas Detection
Tracer
Gas
consists
of
a
non-toxic,
non-flammable,
environmentally friendly (non-polluting) mixture of 5% Hydrogen
and 95% Nitrogen. For this reason, the Tracer Gas can be released
into the environment after the leak detection procedure is
completed.The D740 detects the hydrogen component of the
Tracer gas and because hydrogen molecules are so small, it is an
ideal gas for leak detection.
The Tracer Gas is charged into an empty system at a pressure of
approximately 75 psi (5bar). Run the engine with air conditioner on
briefly to properly distribute the H2N2 Tracer Gas. As hydrogen is
lighter than air, always probe slightly above the suspected leak
area. Begin with the detector set in the
“HI” (4g/yr setting). Move
the probe at a rate of approximately 3
”/second and as close as
possible to the suspected area. If looking for an apparently larger
le
ak, check first at the 7 g/yr “Norm” setting or the “LO” setting.
Once the source of the leak is located and repaired, the Tracer Gas
can be released and the system can be recharged again with
refrigerant. A final check should be performed using an SAE
certified refrigerant gas leak detector such as the D440A or the
D440A-UV.
Leak Size Indicator
The digital leak size indicator remains off normally but once a leak
is detected, a number from 1-9 will be displayed for the H2/N2
Tracer Gas
regardless of the sensitivity setting.
The number will continue to increase or decrease depending on
the amount of Tracer Gasis sensed. The maximum value will be
displayed once the leak source has been located. The table below
can be used to approximate the size of leak
:
Maximum # displayed
Approx. Leak Size (oz/yr)
1 -3
0.15
4-6
0.15 to 0.5
7-9
>0.5
3
