I had some gas lines replaced in the crawl space and the next day after the plumber left I noticed a minor gas smell. I got into crawl space with a HomeFlex leak detector and it is clearly going off full blast around one connection. However, I couldn't see any bubbles with liquid leak detector.
I called the plumber back and he also couldn't see a leak with soapy water. I am fairly certain that there is a leak because I smell it and repeated tests with the HomeFlex detector clearly show the area has gas present. It's a bit of a confined space but not completely blocked.
Why would soapy water not show anything?
Is there any additional way to test for leaks? Pressure test?
I was able to get some bubbles as a proof of leak. Then plumber tightened the connection and said it's fixed. It was not and my HomeFlex meter was still going off like crazy but I couldn't get anymore bubbles. At this point plumber had more trust in the meter, took apart the joint and discovered badly cut edge on TracPipe and fixed it. After that I demanded full pressure test at the meter which he performed to my satisfaction and there are no more leaks and my meter stays quiet on every joint! I definitely think that this inexpensive meter does a good job.