What is the best method of leak checking?
The two best methods are fluorescent dye and electronic leak checking using a tester rated at 0.25 oz per year or less. In certain conditions, vacuum testing and pressure testing with nitrogen are valuable but will not pinpoint the leak. Tip: Recharging the system with a fresh dose of dye may help pinpoint the leak, because dye only lasts so long once it has leaked out. Good current generation dyes last 3 to 5 years (the warranty period). Older or poorer quality dyes last only 6 months to a year. Note: Because of the small molecular structure of nitrogen, it is a good tool for finding smaller leaks. The disadvantage is that electronic leak detectors cannot detect nitrogen. Nitrogen requires a bubble or soap solution to be applied to pinpoint leaks. Because it is almost impossible to bubble check a whole system, this usually limits you to individual components. Caution: Limit the nitrogen pressure to 150psi to avoid personal injury and damage to components.
