View Full Version : ultra sonic leak detector
06-24-2004, 06:11 PM
I know this was discussed a little while back ,but i have an amprobe uld-300 from johnstone for a little over 200. i talked to a friend of mine there i might try to give back at a loss and get a d tech its imbarassing not having something on the the truck that i feel confident is going to find the leak or leaks. ive heard somthing about a transmitter but cannot figure out how it would hook to a system? besides i don't think i'm going to sink any more money into this thing. if anyone has experience with this perticular model and can give me some advice i'd apreciate it .i called amprobe trouble shooter he wasn't very much help thanks in advance
I have one gathering dust in a toolbox. Never have found a leak with it. I now have a Bacharach Informant 2 and an H10. If you can get your money back then go for it.
06-24-2004, 08:35 PM
I have this model and love it. Get system pressure up really high with nitrogen, 350+ psi. The meter has three ranges, I do best with the middle range. The high range is too sensitive, I hear my arm hair touching the cord.
I never use the extension tube or the horn thing, just the meter. You have to point it directly at the leak. Won't work through armaflex. Check coils from inside and outside, front and back. Try to get all around pipes and fittings, not just one side.
06-24-2004, 09:10 PM
I have the AMPROBE ULD-300 and transmitter as well and I think it is the best of all the leak detectors I have ever used. I still have a halide torch, a CPS L-790a, a piece of 3/8" copper on some 3/8" i.d. TYGON tubing and, believe it or not, one of my wife's old stethoscopes. She's a nurse. The Amprobe is my primary search device for all refrigerant leaks.
That transmitter, the UDT-300, is used mostly for enclosed spaces like tanks and such, not for leak searching a lineset or a coil. If you don't test these type of items, you don't need the transmitter.
I had to train my ears to hear the leaks. I haven't missed one yet in the years I've had it. My first method of training my ears was to use a bottle of nitrogen and regulator. I'd let a very slow, steady stream of nitrogen through the regulator and listen with the detector. I'd reduce the flow as much as I could, up to stopping it, and listen to it for a bit to familiarize my ears with the sound of a tiny leak. The rest of the leak sounds were learned through expreience.
I don't always hear a "hiss" from the leak. Sometimes I hear a slow "tic-tic-tic" type sound, sometimes a whistle and sometimes a sound like crumpling plastic or bacon frying. I have rarely had to pressurize a system any higher than ambient temp. pressure from the refrigerant to hear the leak. The only time I'll use nitrogen with the detector is when the system is completely out of refrigerant. Even then, I only have to put about 150 psig pressure to hear the leak.
When I am searching and I hear a potential leak, I'll move the probe away from that spot and listen, move it back and listen, do this a couple of times to be certain something else isn't making the sounds. I've had a few instances where I thought I had a leak but it was only some reflected sound being picked up by my detector. If I'm still uncertain, I get out the soapy stuff and spray the area and look intently at the spot, waiting for the bubbles.
I don't know of anyone who could find leaks right off the bat using one, they've all had to learn how to use it as I did. Your hearing skills are different than my skills and different from anyone else's. You have to learn how to listen with this tool.
I've allowed our apprentices to use my detector and once I taught them how to listen for a leak, they all want to get an ultrasonic for themselves.
Personally, I'll put my ultrasonic and my skill with it up against any other brand of leak detection device. Excepting maybe the tried and true nitrogen and soapy stuff. You pretty much can't miss with that combo.
Having used it for awhile and having gained the needed skill and experience, I'll vouch for this method against all others.
06-24-2004, 10:07 PM
I have never had luck with soapy bubbles.
I just got a AccuTrak VPE unit last week after a post I made here and read the replies.
I have been playing with it, and to day after getting a hit from my Dtek I used the ultra sonic and I heard the leak just like william antley stated.
So like he said I'm going to learn this unit. I can think of a few other uses for it also.
06-25-2004, 09:18 PM
They can also be used to listen to the bearings on blowers and other devices that use bearings to hear when they are getting close to failure. I haven't used it yet for that but, it can be done. I took a piece of 3/8" copper about 6" long, mashed one end flat and cut the flat to a point. I'll put that copper into the tube of the listener and I can use it to pinpoint other types of ultrasonic sounds. It ought to work fantastic for locating failing bearings. Better than the old screwdriver to the ear method by far!
I've had a few instances when nitrogen and soapy stuff were not doing very well for me. I found later that it was because the leak hole was very microscopic and exceptionally slow. I had to boost the nitrogen pressure very high to find that one but, I did. I don't recommend getting the system under really high nitrogen pressure, they can explode if you get them too pressurized. I rarely use more than 225 to 250 psig and that is more than I usually use with the ultrasonic.
[Edited by william antley on 06-25-2004 at 09:22 PM]
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