There are several methods that are commonly used to test for air leaks in a system. One of the most common methods is to use smoke generators. These devices create visible smoke that will easily reveal leaks. Ultrasonic detectors can also be used to help find leaks in hard-to-reach places. Don’t forget to do a preliminary visual inspection and check all connections and seals. For accuracy, you can do a pressure test by filling the system with air under increased pressure and observing the changes. I hope this helps solve your problem!