allsun Ultrasonic Vacuum Leakage Detector Pressure Transmitter Finder 40KHz Air Leak Monitor with LED Indication(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.

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.

Could not detect massive under ground, returned for refund

you get what you pay for. not the best but for the price i believe it is decent

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!

This reasonably priced device will detect leaks, but in my experience it is not sensitive enough. I tried it on a very slow leak but was not able to get any signal. That leak was easily detected with soapy water, and even a much smaller leak would have been revealed that way. Where this device did work was with much larger leaks. However, those leaks were of a size that one could hear them in a quiet room by putting an ear up close. It is possible that the device would be capable of taking it down another level, but it is not adequate for the very slow leaks where one needs the most help to detect. For the larger leaks, say in a compressed air system, the device offers the benefit of having a directional microphone that can be pointed at a suspect joint or fitting and that is a good capability. It also means that one might need to rotate it all around the joint to not miss the leak. In summary, the low tech soap bubble method is far cheaper and much more sensitive, but this device might be useful for larger leaks in certain applications. It is no match for the more expensive dedicated instruments optimized for HVAC applications.