Appliance flex hose leaks

[JackBurton]

The way my gas cock is oriented behind my range prevents me from installing a test gauge on it. So I figured I'd put the test gauge on a flex hose and attach the flex hose to the gas cock. This setup is not holding air long enough (>3 psi for >1/2 hour) regardless of how I tighten the flare nuts on the flex hose--kinda tight or very tight. Leak detector bubbles ever so slightly on the flares when I have 15 psi on there. I've tried two brand new flex hoses and they both seem to leak at the flares.

When I plug the gascock and set the test gauge up in the basement on the supply end of my new line, it holds air indefinitely. So all the black pipe joints and any place pipe threads are involved seems to be fine.

I imagine people don't often pressure test through a flex hose so I think these things leak more than people realize. Is there an alternative to the commonly available flex hoses with flares? I suppose the flares are there to make it easy to tighten without the hose spinning but something involving pipe threads ONLY seems like it would seal much better.

 

[Cacher_Chick]

A flared line should only be tightened one time, and over-tightening will cause leaks just as often as under-tightening. If the fitting has been tightened sufficiently and there is still a leak, the flex-hose should be thrown away. Also inspect the tapered male flare end, as if it has any sign of scratching or scoring of the tapered sealing surface, it too should be replaced.

 

[Sponsor]

 

[Dj2]

A visual inspection is needed to see what you have done.
If you have a leak, there must be a problem with the flex (the way you install it or its size). Gas connectors don't require that much tightening to the point of no return.

 

[hj]

WE ALWAYS test through the flex "hose", in fact it is a requirement of the test that we test EVERYTHING, except the appliance itself, up to the appliance connection during the pressure test.

 

[JackBurton]

A flared line should only be tightened one time, and over-tightening will cause leaks just as often as under-tightening. If the fitting has been tightened sufficiently and there is still a leak, the flex-hose should be thrown away. Also inspect the tapered male flare end, as if it has any sign of scratching or scoring of the tapered sealing surface, it too should be replaced.

That's interesting because I got the leaks to stop by tightening and the loosening the flare nuts a few times. It kinda seems like the flare was not seating correctly initially.

 

[JackBurton]

WE ALWAYS test through the flex "hose", in fact it is a requirement of the test that we test EVERYTHING, except the appliance itself, up to the appliance connection during the pressure test.

So that leads me to other questions then. What pressure do you test to and do you throw the flex line you used for the test out?

The labels on the Brasscraft flexlines say they are rated to 1/2 psi and they are not to be re-used. As far as re-using them, I'm not sure whether they're worried about the flares or they're worried that the hose was flexed when the stove was pushed in potentially weakening the hose walls. I did get the leaks to stop by loosening and tightening the flares a few times. Does that count as "re-using" the hose? And if it does, how can you test through the flexline without reusing it? Obviously you have to take the test gauge off which is gonna involve loosening a flare.