What color is it? My white one just detects when I bump the tip but never detects leaks. What it really excels in is killing batteries. Best detectors I have found are H10 and tifzx.
White one is garbage IMO. Never could get the white dtek select to work properly. The grey one with blue back works flawlessly for me though. I have heard some mention about an improved tip that can be had for free somewhere to fix a known issue, but mine worked fine from the start. Just keep it charged and your good to go. Stay away from the white Dtek selects!