The selective gas tracer SelectH₂ from Herth+Buss is equipped with two gas sensors and a suction pump that work like an artificial nose and only react to hydrogen. Petrol and oil fumes no longer have a negative influence on the measuring result. This is the most striking difference to conventional devices that react to the refrigerant R134a. 

Invisible hazard
The extent to which a substance is harmful to the environment is given as its so-called GWP-value (Global Warming Potential).

The latest studies revealed that the GWP value of R134a is about 1300 times higher than that of CO2. According to manufacturers, the leak rate of modern air-conditioning systems is about 8 %. Experts estimate that about 820 tonnes of the refrigerant R134a escape each year. This corresponds to one million tonnes of CO2, whereby the loss through accidents and repairs was not taken into account.

For this reason, the new chemicals climate protection directive was introduced in August 2008, subjecting workshops to the legal obligation to eliminate any leaks in air-conditioning systems before they are refilled with refrigerant.
In other words, refrigerant may no longer be used for leak detection, as was previously the case.

Leak detection using the SelectH2 is as easy as it is efficient. The air-conditioning system is filled with forming gas that is made up of 95 % nitrogen and 5 % hydrogen and is not explosive in this concentration. In the meantime, the gas tracer should have been switched on, since it has to be pre-heated for about 45 seconds until it is ready for use.

Now the passenger car engine is started up briefly and then stopped again, so that the non-toxic and non-combustible forming gas can be distributed evenly in the air-conditioning system.

The air-conditioning system can be monitored both in the part-filled and empty state. To increase the efficiency of the leak detection process, however, professional evacuation of the system is recommended before detection. After the leaking spot has been repaired, this should be checked again using forming gas before the system is refilled with R134a. The forming gas can then be discharged by opening the valve at the service connection.

• False diagnosis caused by oil and petrol fumes can be excluded, since the sensors only react selectively to the hydrogen contained in the forming gas.
• All closed systems can be checked, providing the forming gas can be introduced into them (e.g. radiator, pneumatic brakes, engine bleeding and run-flat tyres)
• The device is also suitable for car dealers or experts evaluating accident vehicles, since a faulty air-conditioning system can have a major influence on a vehicle's value
• Faulty heat exchangers can also be detected WITHOUT dismantling the dashboard
• The device is unique among mobile devices across the world, and it is available exclusively from Herth+Buss Elparts

SelectH2 Selective Gas Tracer
Part number: 95980002

Note: Leaks and thus refrigerant loss pollute the environment! We recommend having air-conditioning systems serviced once a year, including leak detection using the SelectH₂ from Herth+Buss.