After wasting probably a couple of thousand dollars over the years on electric leak detectors, everyone started using UV dye and that’s what I use. The #1 source of refrigerant leaks is the service valves. There really isn’t much left to check. Compressor or lines hoses oring a or connections, evaporator and condenser. Also if you see UV dye or oil on the compressor around the pop off valve, you could have a restriction, too much oil, or fans not working correctly. Even if the service valves are not leaking now, after you connect the hoses or machine and disconnect them, it may now start leaking! Large leaks, just take the air hose with a rubber tip blow gun and pressurize the system with whatever you got in a pinch, plain dry air. It’s already open to the atmosphere, now you can find a major leak and not waste refrigerant. Biggest mistake is when you find no leak and assume it must be the evaporator. Maybe not, maybe you just didn’t look everywhere. It’s hard to trust 100% those electronic leak detectors. It’s hard to trust what you can’t see.
Good points 👍 Worked at a Goodyear in my twenties and the owner was doing some a/c work in the next bay. Went on a road test, heard noise and then see something tumbling in the rear view. Drove back around and see the shop refrigerant tester laying out in the road. Was about to run out and pick it up when a truck smashed it. Got back to the shop and asked John if he forgot something. He set it on the bumper of the pickup I was working on 🤣
