Gas Leak Range Connection

[jyl]

I had to disconnect and move my range, and when I reconnected it I got a gas leak at the coupling between the valve and the flex hose. Not a big leak but I can just barely smell it and my $28 cheapo Amazon gas detector certainly detects it.

The leak seems to be right where the dull yellow brass valve body and the shiny silver steel coupling thread together. I can sort of “feel” the leak on the underside of the joint (wet fingertip, open and close valve with fingertip at the suspect location). I can’t see that place directly but have put my phone camera down there and don’t see anything obvious (like, no evident crack in valve body).

I’ve tried assembling that joint with the thick yellow gas pipe tape, then with PTFE pipe thread sealant, then with a sh-ton of said sealant, and I’m positive the coupling is seating all the way down in the valve body. I’ve torqued it at least as much as it was originally torqued (it was really tight, like two big wrenches needed).

That’s a $35 new flex hose and coupling in the picture, and . . . still leaks.

Any thoughts? Is there a magic pipe dope that works best? I have the valve turned off and will call a plumber if needed, but this seems DIYable?

[cabmandone]

Put some dish soap on the fitting. Some pipe thread compounds will cause a false reading on leak detectors. If you don't see small bubbles forming with the dish soap, you probably don't have a leak.

That steel fitting should be a standard 1/2 male pipe thread to 1/2" flare fitting. If you question the fitting at all, you can easily replace the fitting and reuse the hose.

[jyl]

Originally Posted by cabmando

Put some dish soap on the fitting. Some pipe thread compounds will cause a false reading on leak detectors. If you don't see small bubbles forming with the dish soap, you probably don't have a leak.

That steel fitting should be a standard 1/2 male pipe thread to 1/2" flare fitting. If you question the fitting at all, you can easily replace the fitting and reuse the hose.

It’s definitely leaking. I can smell it if I get down near the valve and fitting and my handheld gas detector is alerting as soon as I put the sensor near that spot.

And it’s a new fitting, came with the hose - when I couldn’t stop the leak using the old hose and fitting, I bought new and no joy.

This connection had what seemed like white tape on it, when I took it apart. The valve body to elbow connection has some blue, hardened sealant stuff on it.

I mean WTF, it is irritating as hell.

[cabmandone]

Try using soap to pinpoint what exactly is leaking. Start at the nut on the line then work back onto the valve. Just let the soap drip down onto the fitting until it's all the way around the fitting. You should see bubbles if it's leaking bad enough that you can smell it. Did you back up the valve with another wrench when you removed the old line? I've never had that type fitting leak if installed correctly.

With the threads almost bottomed out on the metal flare fitting, I'd be amazed if it's actually leaking there unless you've got thread issues on the valve itself.

[herr_oberst]

It looks like the coupler between the ball valve and the flex is bottoming out into the ball valve threads. That doesn't make sense, because you have a gas ball valve, and the coupler appears to be the one that comes with the flex line.

Should be tapered threads and there should be 3 or 4 threads showing after you get it snug....

[jyl]

Yes, used two wrenches. I’ll work on it tomorrow, pinpont the leak. The coupler threads aren’t tapered, it screws fairly easily all the way until it bottoms out. Yes, it came with the flex line.

[creaturecat]

perhaps the ball valve was distorted due to over torquing?

[1990C4S]

I would replace the shut-off.

Then use something like this: https://www.amazon.com/Rectorseal-31631-Tru-Blu-Pipe-Thread-Sealant/dp/B0012YO0Z4

[drkshdw]

It's very easy to crack brass fittings by over tightening them while trying to snug up a leaking connection, especially with newer brass from 'over there'. Don't ask how I know this.

[fintstone]

I use something like this for gas connections. Just read the label to ensure that you choose the one that suits your application. The local pros do the same.
https://www.oatey.com/products/oatey-great-white-pipe-joint-compound-with-ptfe--275767012

[masraum]

Originally Posted by jyl

Is there a magic pipe dope that works best?

I was going to say that you were the "magic pipe dope that works best" but since you've been working at it for a while and it still leaks....

Good luck. I did something similar years ago, and had a leak. In my case, I didn't have to do anything magic, I just needed to tighten it up a little. But then I hadn't gotten it super tight to begin with.

Good luck. I'm sure the brain trust will put you on the right path!

[fintstone]

I have never used a gas detector. The way I troubleshoot something like this (hard to locate gas leak) is to turn off the gas source, clear the air a bit and the turn it back on...then immediately run a lighted match or lighter around the hose. A small leak acts like an orifice and you get a tiny pinpoint flame where the leak is. Then extinguish the flame, turn off the source and fix. Best if you have a helper to turn the gas on and off. That is the old fashioned way...just don't do it without clearing the air of gas for a few minutes first.

With the white paste pipe dope, you do not usually have to tighten quite so much so less chance of deforming fittings.

[VINMAN]

Is the brass fitting cracked along the threads? Iv'e seen that happen a lot from being over-tightened.


.

[look 171]

Buy another shut off. Its only 10-15 bucks and problem solved. soap and a bit of water is your friend for checking leaks. We use a torch at times. Seriously.

[cabmandone]

If it's leaking enough that you can smell it, I'd seriously advise against using flame to detect. Soap...

[jyl]

I guess the valve needs to be replaced.

[Bill Douglas]

Gas fitters put a pressure gauge on the main supply and leave it for a period of time (couple of hours?) and measure the amount of loss. Regulations around here are very stringent and the amount of loss allowed is next to nothing.

Here is a pic of a house where the gas man stuffed up

[1990C4S]

Originally Posted by jyl

I guess the valve needs to be replaced.

Just leave it like that. Problem solved.

[cabmandone]

They call that "flaring" in the oil and gas industry don't they?

[jyl]

And indeed, where I couldn’t actually lay eyes on it (facing the ground)



All fixed, except for patching the hole required to thread on the new shutoff valve - I guess the prior guy threaded it on at the elbow, not sure.