allsun Ultrasonic Vacuum Leakage Detector for HVAC & Automotive, Pressure Transmitter Finder 40KHz Air Gas Leak Monitor with Dual LED,2 Sensors & Headphone(NOT Detect Pipe/Plumbing/Tire/Pool)

Worked amazingly well after failed attempts with a halogen leak detector and 300 psi nitrogen and soap bubbles. I found the leak in my Gree AC heat pump in minutes after spending $1000 over the years on recharging. The leak was a manufacturing defect with a pinhole under perfect evaporators fins. Pulled away the fins and brazed the pinhole shut, vacuumed and recharged. I understand using the ultrasonic noise generator it is great for finding water leaks in cars an other weatherstripping.

Works well on most leaks. Perfect for what we got it for.

I tested the device on my nitrogen tank by simulating a leak. It only detected what was already audible to me. If its detection capability is limited to what I can hear, then I fail to see its value. I spent the entire day yesterday searching for a leak based on my trust in this ineffective tool.

Received it today, and I played around with it. The transmitter works only 50% of the time when I switch it on. The LED power indicator is on but no ultrasonic sound comes out. I have to turn it off and on a few times before it kicks in........ Quality control is definitely an issue with this product. If the transmitter is not reliable, then there's no reason to trust the receiver. You get what you pay for, i suppose.

For a tool that doesn’t get a lot of use this one can really save the day. I had a vacuum leak on my car and I couldn’t locate it over all the other engine noise. This tool disregarded the other engine noise and alerted once I got close to the source of the leak. It recognizes the frequency noise at the source of the leak.

Learned about this item on a Maple Syrup forum. Ever since a local distributor stopped selling a similar united I have been looking for an option. This was recommended on a Maple discussion group. Used today to check for leaks on a vacuum pump area and two releasers. Found a cracked fitting on the vacuum pump. I wish it had a more visual indicator (ramp of lights vs a single light when a good leak is detected). I would recommend it.

I gave it 2 stars (instead of 1) because it can detect its own transmitter. As far as the reviewer who said they found a mini split leak, it must have been a loud leak. As other reviewers have said, it can only detect what you can hear yourself. Maybe it would have some use in a noisy environment. The fact that the manufacturer states it cannot detect a leak in a tire should be a big clue. I made a small leak out of a gas cylinder. When it was pretty loud (and I don't have great hearing...) the thing detected it and the click rate went up in the earphones. As the volume diminished the clicks went back to normal but I could still hear the leak and my ear was a foot away and the detector was right on it. From the get what you pay for dept.

I had an internal leak in a brand new transmission that was allowing oil into the flywheel housing. Soap could not detect it when 5 psi was applied to the transmission housing. I got the tool quickly and started testing. I found a pin hole in the casting of a bearing housing. This was a huge help!