CPS LS790B Leak-Seeker - Electronic Leak Detector with 0.25 oz/yr Sensitivity, Flex Probe, and High-Intensity Bar Graph Display

ok. I read the manual quick and got an idea of how it works, then I started using it. I usually see how I am supposed to use it, then I start playing and make it work for me and how I'll use it. This is my recommendation. First, the detector works great. I had a town car with a leak that I couldn't find otherwise and knew it was time to get a detector. Let me begin by saying...if you are a mechanic, stop wasting your time and refrigerant. Get one of these. It will save you whatever it costs on the VERY FIRST repair. I found a leaky evaporator and a leaky low side valve within 10 minutes. Both were fixed...no more leaks. Holy cow I wish I would've bought this a while ago. Forget any other method. A small leak you will NEVER find without one of these. (Before I get into it, if the system has leaked out, you need to charge it because it reads the refrigerant, not just a leak. If that isn't implied you should understand that. You need to evacuate the system and put a charge to it. Vacuum pumps are cheap and you need to do it right anyway because you'll eat compressors if you don't get the air/condensation out. the oil that's used in the systems absorb that stuff and ruins it) Ok. Here's how I use it. I gauge the leak by first turning up the sensitivity to max and waving it around the engine bay. As others have said, if it's a bad leak, it will just constantly go off. That's ok. At least you'll know it's a large leak. I start max sensitivity and wave it around...no beeping. Good. Small leak. Then start working around all the components. If it's going off like crazy, back off the sensitivity. My leaks were really small, so I worked around with max and found them. Start at the obvious spots...around the compressor, condensor, where the lines connect to each other or other things, fill valves. It will most likely not have a random hole in the middle of a steel tube. It will be something that makes sense usually (leaking seals, valve, etc.). And that's my advice. Hope that helps someone out. I am an ASE master tech if anyone is wondering.

I've tried to work this out with CPS, but they clearly don't stand behind their products. This model, the LS790B has performed remarkably well for the few we used on our production lines over the last decade since R410A was implemented, but their latest designs DO NOT WORK WITH R490A. Do not buy this model if you intent on using it for R410A.

Not only is this tool USA made, it is of very high quality. I used this same unit at the dealership for vehicle A/C work and it performed flawlessly. Easy to use, compact, detects ALL refrigerant types. This is definitely a professional tool, and a great value.

This is the best leak detector I have owned. It is really sensitive to small leaks. I owned a Inficon leak detector and it does not even compare to this CPSLS790B leak detector. This CPs detector will pick up the smallest leaks with no effort. The only thing I do not like about it is the alarm sound has a funny sound to it. But man this thing works. I'm not going to use my old Inficon leak detector no more after buying this CPS tool. CPS is much better. I don't think this detector does the new refrigerants. Not 100% sure on this but I believe I'm correct. Research this to be sure. I no it does R22 and R12. I would buy another one .

Strangely enough, was shipped the more expensive LS780C, in a box labelled as LS790B (and the unit's serial number matches the box). Works as expected, but have to move slowly along lines. Very sensitive (oil based anti-rust spray sets it off, as does the insulating foam under the dash) - BUT it did find a leak, and I was able to fix it. The sensor tip worked itself loose and started giving me full alarms every 5 seconds - until I tightened the tip (then all good). VERY useful tool, but for very slow leaks (emptying in a year), I recommend combining with UV dye, and maybe even some pro-active aging seal replacement.

I am really impressed every time I buy something from CPS, they make real tools, that look real durable, with style and functionality. This detector has many useful functions, alarms and levels on sensibility that are a must for every AC tech. I hate cheap Chinese tools that in the end makes you look like a cheap technician, I love CPS products and I support things made in the US, I understand that companies have to cut costs and manufacturing overseas is a way to do it, but they are making customers pay for something less than they expect.

U get what u pay for. Works for huge leaks not so much for little ones.

It works good for the price paid, and helped me find a leak in my tractor's A/C. I wish it was a bit easier to use, but after reading the directions a couple times, it finally made sense. 4 star product, good value for the price, but I knocked it down a star, for the sketchy instructions.