After great effort, I just now found my very slow propane leak (and I will soon prepare a fascinating ;) report on the many things I learned while trying to find it). Bottom line – the leak is at the point that the external barbecue fixture connects to the propane system.What I want to do is remove the barbecue fixture – we never use it. And I want to cap off the stub or nipple that "tees into" the propane line. The pipe is galvanized. It appears to have an ordinary pipe thread -- not a flared brass gas fitting.I am planning to unscrew the existing reducing bushing (I think that is what it is called) and replace it with a galvanized cap. I will use teflon gas tape at that joint. My real question is this: I don't want to put any stress on the other galvanized propane lines underneath the trailer. I will hold back on the galvanized nipple with a pipe wrench while unscrewing the existing reducing bushing. The bushing is very rusty -- I anticipate having to use a lot of force to unscrew it. I'm planning to spray it with WD-40 a day or so before unscrewing it, to try to loosen the threads.Does this sound like the right approach? I am not a plumbing or propane expert, as you can tell.Thanks in advance for your suggestions!!

That’s how I would do it. Use pipe dope on the threads. Turn off gas first

Should be black iron, not galvanized, but other than that, it’ll be fine.

YEP....Always use 2 wrenches 1 to HOLD existing pipe and 1 to use to remove other pipe/nipple etcPipe dope the threads (yellow tape will work....several wraps)

i prefer 'Kroil' or 'PB blaster' much better penetration, bushing will come out easierI would use a Brass cap, and Yellow Teflon tape is for Gasses, white Teflon is for liquids

profdant139 wrote:I'm planning to spray it with WD-40 a day or so before unscrewing it, to try to loosen the threads.Contrary to popular belief, WD40 is not a penetrating lubricant! Get some PB Blaster. Best stuff on the face of the planet for what you are doing.On a related note, personally, I prefer pipe dope to PTFE tape.

Capping off a propane line: need tips and tricks!

20 Replies

profdant139
Explorer II
May 24, 2019
It looks like my local Lowe's has a selection of black iron. Galvanized might work, but why take a chance?

Again, continuing thanks for all of the helpful comments!!
Lantley
Nomad
May 24, 2019
smthbros wrote:
"Galvanized pipe can flake and clog orifices an small openings within your appliances."
This is no longer an issue due to a change in the galvanizing process which happened several decades ago. None the less, it would be wise to check with the governing authority for your jurisdiction. Until about 30 years ago, copper was unapproved for natural gas piping in my jurisdiction. It is now approved.

You maybe right that it is an old tale at this point nevertheless many jurisdictions do not allow galvanized pipe
smthbros
Explorer
May 24, 2019
"Galvanized pipe can flake and clog orifices an small openings within your appliances."
This is no longer an issue due to a change in the galvanizing process which happened several decades ago. None the less, it would be wise to check with the governing authority for your jurisdiction. Until about 30 years ago, copper was unapproved for natural gas piping in my jurisdiction. It is now approved.
Lantley
Nomad
May 24, 2019
profdant139 wrote:
If the pipes are black iron and not galvanized steel, can I use a galvanized cap to cap off the line? The metals are not so dissimilar that they will cause electrolysis, are they?

And if I need to get a black iron cap rather than a galvanized cap, who would carry such an item?

Sorry if these are naive questions, but I have stepped outside my comfort zone here.

Galvanized pipe can flake and clog orifices an small openings within your appliances. Small pieces of the galvanized material flakes off.
Don't be obsessed with using galvanized pipe. Black pipe fittings are readily available.
Galvanized pipe is not used for gas work due to the potential for flaking and clogging.
profdant139
Explorer II
May 24, 2019
If the pipes are black iron and not galvanized steel, can I use a galvanized cap to cap off the line? The metals are not so dissimilar that they will cause electrolysis, are they?

And if I need to get a black iron cap rather than a galvanized cap, who would carry such an item?

Sorry if these are naive questions, but I have stepped outside my comfort zone here.
Edd505
Explorer
May 24, 2019
Chris Bryant wrote:
Should be black iron, not galvanized, but other than that, it’ll be fine.

That was my thought, gas = black iron. I prefer the yellow tape, less mess.
profdant139
Explorer II
May 24, 2019
phil, this was not an extend a stay. Just an ordinary external bbq fixture. Not sure why the leak formed -- I am going to examine it closely after I remove it. Right now, there is no way to see the area with the leak -- it is about an inch below the bottom of the trailer.

Gonna get some of that PB stuff and let it sit for a day or so before I move ahead with removing the fixtures.
TurnThePage
Explorer
May 23, 2019
I think when I did it 10 years or so ago, the fitting came of pretty easily, and I just screwed a cap on with teflon tape and a little grunt. It's held up fine ever since.
pnichols
Explorer II
May 23, 2019
profdant139 wrote:
After great effort, I just now found my very slow propane leak (and I will soon prepare a fascinating ;) report on the many things I learned while trying to find it). Bottom line – the leak is at the point that the external barbecue fixture connects to the propane system.

What I want to do is remove the barbecue fixture – we never use it. And I want to cap off the stub or nipple that "tees into" the propane line. The pipe is galvanized. It appears to have an ordinary pipe thread -- not a flared brass gas fitting.

I am planning to unscrew the existing reducing bushing (I think that is what it is called) and replace it with a galvanized cap. I will use teflon gas tape at that joint.

My real question is this: I don't want to put any stress on the other galvanized propane lines underneath the trailer. I will hold back on the galvanized nipple with a pipe wrench while unscrewing the existing reducing bushing. The bushing is very rusty -- I anticipate having to use a lot of force to unscrew it. I'm planning to spray it with WD-40 a day or so before unscrewing it, to try to loosen the threads.

Does this sound like the right approach? I am not a plumbing or propane expert, as you can tell.

Thanks in advance for your suggestions!!

I'm curious regarding the source of your leak ... was that an "Extend-A-Stay" adapter fitting that developed a leak?

If so, I was thinking about installing one in motorhome's propane system for use of a 5 gallon propane tank to supplement the main tank on long campouts - plus maybe also power our outdoor BBQ ... but have held off because I didn't want to introduce another potential leak source into my propane system.

Here's a link with a photo as to what an Extend-A-Stay adapter is for a built-in propane tank, which may be similar to what you have on your TT for use with an externall BBQ:
http://www.rv-project.com/projects/extendstay.php
philh
Explorer II
May 23, 2019
Pipe dope ONLY goes on threads... not on the flange like the idiot (a master plumber to boot) that installed a water heater on my first travel trailer before I bought it.