Fixing small gas leak?

[Joe J]

We bought a used gas dryer and it came with a flex gas line. Hooked everything up and we smelled gas. Called the gas company and they came out and identified the problem as a leak in middle of the flex line. While there, he had his sniffer out and said we had a slight leak on the water heater gas supply line. He put some wrap on it and said it would be fine until it was tightened up. I'm stumped how to do that. ½ black pipe runs down to a T and the leak is in the center of the T that supplies gas to the water heater. There is a shutoff and union in the line. Other side of the T drops down with a 3" nipple and is capped. There is about a 6" run from the center of the T to the water heater. If I open the union and begin to tighten the line into the T, at the same time I'm tightening at the T, I'll be loosening the line that runs to the water heater. If I try and rotate the T, I'll be rotating it away from the supply line and it won't reconnect, unless I managed to get 1 full turn more. The gas company guy said it just needed tightening. I'm thinking that actually means I need to completely disassemble this from the union down, clean all the parts up and start over with new pipe dope and reassemble from the heater back to the union. Or am I missing an easy fix?

[jamesgangnc]

No, you're right. You have to back down from the union. And that nipple on the T needs to point down. It's a trap sort of thing. There is teflon tape for gas now if you prefer that. It comes in a yellow roll. Not supposed to use the regular stuff but beats me why.

[dpb]

Joe J wrote: ...

Yep (and nope)... :)

Check on condition of the pieces, of course, before reusing.

Is the leak confirmed at a threaded joint not a pinhole failure in the body of the tee or similar?

There is a water trap somewhere in the line I presume? Be good time to clean it out if so, or install one if not.

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[dpb]

jamesgangnc wrote: ...

No difference other than the yellow is thicker so takes fewer wraps to get sufficient material for the gas seal...

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[jamesgangnc]

That's it. Well I coulda just put more on. Oh well too late. I have some yellow and lots of regular :-)

[dpb]

That's it... :)

Actually, there's one side benefit of the thicker film that can be significant on gas. It doesn't tend to shred so badly into those tiny little threads that if you ever get one inside a gas line can plug orifices, etc.

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[Jay-T]

I think it depends on exactly where the leak is.

When you say the leak is in the center of the T, do you mean the leak is where the threads of the T meet the short horizontal pipe that goes to the hot water heater?

If so, I would say to do this:

1) Shut off the valve. 2) Loosen and disconnect the Union joint. 3) Loosen and take off the vertical short piece that comes out of the bottom of the T. 4) Loosen and take off the vertical pipe that comes out of the top of the T. 5) Loosen and take off the T from the short horizontal piece that goes to the hot water heater. 6) Use gas pipe thread sealant or yellow gas pipe thread sealing tape and re-attach the T to the short horizontal piece that goes to the hot water heater. 7) Use gas pipe thread sealant or yellow gas pipe thread sealing tape and re-attach and tighten the vertical bottom pipe and vertical top pipe. 8) Re-connect and tighten the union. 9) Open the valve. 10) check for leaks by smell and/or soapy water around the joints.

If the leak is where I suggested above, the T probably only needs to be tightened by 1/2 turn to seal the joint, but it's better to disconnect it all and re-do the joints with new sealant or tape in my opinion.

[jamesgangnc]

I'm usualy pretty carefull to make sure I have it a little back from the end on everything. Lots of stuff, gas, water, gasoline, have small holes at the ends or somewhere:-)

[Paul Oman]

-------- when done with tape repair - test with a match! wink wink!

[Steve Barker]

That IS the easy fix. The hard one would be if you had no union.

[Bob F]

I've had far better luck with pipe dope than with teflon tape in getting good tight joints.

[Joe J]

____________________________ Yes the leak is at the threads of the T that leads to the short horizontal piece that runs to the water heater.

Joe

[Stormin Mormon]

Yes, disassemble from the union, to the leak.

The white teflon tends to fall apart, and the small pieces clog gas valves or orifices.

[Stormin Mormon]

That's profound. And true.

[Stormin Mormon]

Rectorseal #5 non hardening, works for me. Until it hardens in the can, and then I have to buy another can.