Have 1″ iron pipe for gas lines that we cannot find minor leal in line.
we have tried soapy water and dish soap alone, increase pressure from 15psi to 30 psi than to 60 psi with no luck finding where leak is occurring. We are losing 10 psi over an hour (from 15 to 5) this is a new installation @150′ with 6 valves and many fittings.
any one have an additional ideas? could i use water, an liquid, or some gas that may be more detectable than compressed air
Replies
The gas company has ultrasonic detector that pick up the sound of the leak. But they may not want to look at customer-owned lines. A instrument rental firm in a big city might have them.
Charging with water would create drips somewhere. But soapy water usually works quite well. It does take some practice to notice really slow leaks. Sometimes the extra (small) bubbles just roll down the joint without getting big and obvious.
A gas sniffer coul;d help; many plumbers and home inspectors will have them, but be aware of false positives ()they will react to more than just gas, including fresh pipe dope. Use a sniffer to find a possible spot then test with soap.
Of course, with the quick ..... Ahhh, never mind, someone might actually try it!
Check your air inlet needle valve. Sometime dirt accumulates there and will not let the needle valve seal properly. And check around the testing gauge.
A valve could be leaking internally. Cap after each valve before appliance regulator.
Half of good living is staying out of bad situations.
Edited 8/26/2002 11:34:53 PM ET by rez
Have found with some leaks (ok bear with me on this) on aircraft fuel tanks that when we do a pressure check that incressing the pressure only makes it harder to find the leaks. Try reducing the pressure to say 5 or even 2 psi, then add the soap to all joints. If nil fix, try even the lines themselves. When a leak is small enough the soap will not bubble at high pressure but will do so at low pressure.
Next would be to use a lighter and when the house explodes no more problems as there is no more house. OK DON'T DO THIS.
Jet makes the good point that a high pressure leak can blow all the soap solution away before you've had a chance to see tghe bubbles grow.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Add glycerin to your soap mix. Available at the drug store. In a pinch get Cornhuskers lotion as it is mostly glycerin. It thickens the stuff to a goop so that the bubbles will last longer and more obvious. Add enough and they can last for almost an hour. When applying it use a blush and get a heavy coat on all the connections, where the pipe crosses anything with an edge, don't forget at straps that may rub, and under any other pipes that might leak.
A slight leak from a drain pipe of sulfuric acid drain cleaner can eat pinholes in pipes. I have seen it cause a water leak in copper tubing directly below a coupling in a drain line. The plumber who ran the tubing in one piece to a refrigerator swore that it couldn't leak. It was in a wall that stayed wet. He swore it must be a roof leak. I must, in the plumbers defense, say that it had to be one of the rarer occurrences. Use a strong flashlight and a mechanics mirror to check for bubbles. Good luck.
I guess the next thing I would try is taking the valves off, one at a time.
(How can you recognize a DEC Field Engineer with a flat tire? He's the guy changing each tire in turn to see which one is flat.
How can you recognize a DEC FE who's out of gas? He's the guy changing each tire in turn to see which one is flat.)
Dual- So where did you find the leak?
Half of good living is staying out of bad situations.