By applying soap solutions or similar, (typically sprayed or painted on) leaks can be located by watching bubbles forming in the leak area.

An ultra-violet dye circulating with a system liquid permeates through the leak and is able to be detected using an ultra-violet light.

The test object is filled with the search gas or the search gas/air/nitrogen mixture to which the leak detector is sensitive. The leak detector is equipped with a sniffer probe, whereby there is a low [...]

Hand held leak detectors using the detection of pressure escaping through the leak source by listening for gas leaking. These leak detectors are very efficient but are limited by the need for absolute quiet during [...]

Evacuate the  system using a vacuum pump. A vacuum pump cannot achieve a vacuum better than the Saturated Vapour Pressure of any moisture (water) or other contaminants that may be in the system or vacuum [...]

System must be evacuated to less than 1.0 Millibar absolute. After the system has been evacuated the vacuum pump should be isolated from the system. As a guide, with constant ambient conditions, the vacuum should [...]