Advice about delicate gas plumbing situation? (1 Viewer)

e9999

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I want to put a NG grill outside my house.
There is a gas pipe coming out of the wall for that purpose (well, at least I think it's a gas pipe).

Potential problem: the pipe and cap are rusted (20 years in the elements) and it could well be that the cap will be difficult to remove if rusted in place. The issue is that I don't want to take any chance to have the pipe itself turn with the cap as it could then become loose someplace inside the wall and if the sealant is broken there I could have a leak and have to dig a big hole in my wall.
So I need to remove this cap without taking any chance of having the pipe spin. There is not a lot of room between the wall and the cap, maybe an inch and a quarter.
I also don't want to risk crushing or damaging the pipe by putting a huge pipe wrench or similar on it.
Of course I can put on plenty of penetrating oil over days to help. But looks like some sort of goop compound that may well have hardened and sealed things up.

My question is:
how do I loosen the cap without risking issues with the pipe?

Or should I perhaps forget that approach as too risky and drill and tap a hole in the cap or grind the cap down or wheel cut or something like that without doing any twisting?
Of course it's gas (I think) so drilling and grinding and all that might be iffy too. I'd rather not have the house blow up, everything else the same... :) If it comes to that maybe I could turn off the gas, burn as much as possible in the kitchen, drill a small hole at low speed, and fill up with water or blow plenty of air to dissipate the remaining gas before grinding?

Or maybe a giant nut splitter if there is such a thing?

And no, I'd rather not put a torch to the thing... :D

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before you do anything call the Gas Company and have them pressure test the line and replace that pipe if need be, you just don't hook up without knowing.....unless you're scottm.
 

e9999

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before you do anything call the Gas Company and have them pressure test the line and replace that pipe if need be, you just don't hook up without knowing.....unless you're scottm.
why would the gas company do anything? this is all on my side of the meter.
 

scottm

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Can you access and hold the pipe from inside? I'm guessing not since you're concerned about turning it. Looks like pipe dope, it may not be as rusted on as you think, but PB Blaster would be an extra help. I doubt you'll crush the pipe with a pipe wrench, I've twisted pipe like that and it hadn't crushed yet. Have you located the valve to shut off this line and made sure it's closed?
 

scottm

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before you do anything call the Gas Company and have them pressure test the line and replace that pipe if need be, you just don't hook up without knowing.....unless you're scottm.
Is there anything you're not ignorant about and afraid to do yourself?
 

scottm

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And he's just gotta drag my name into it, doesn't he.

e, what kind of NG grill are you going with? My son-in-law looked around but only found high-end grills in NG, or conversion kits for the smaller grills. Starter home, just the two of them, he's looking for a smaller one.
 

e9999

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let's keep the Scott wiring battle feuds out of this, pretty please.

Charles, anywhere else your talents might be needed?

no, no access from inside that I can see so far.

(this is for a small older Weber Elite 500 series NG)

It might be possible to put a big wrench on the pipe, a big guy on that wrench to hold it still and I wack a small wrench on the cap? Still iffy though, the jolt might propagate inside the wall.

I'm leaning toward cutting the cap open. maybe a slow hand hacksaw might be safe?

Did anybody ever see sparks out of drilling a hole?
 
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scottm

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Two guys will have no more leverage than one guy working two wrenches against each other. You wouldn't want to bang on the end of that pipe not knowing how it's supported inside, but if you lay a hammer or block of steel on one side of the cap, and whack the other side a few times, it'll help loosen any rust in the threads.
 

scottm

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Shut the gas off at the meter, if there is pressure in the pipe and you loosen the cap gas is gonna come out.
There should be a valve in that gas line inside, I wouldn't use the line if there isn't a shutoff for it. Household pressure is very low, not much will come out when you open that cap.
When the gas reaches a customer's meter, it passes through another regulator to reduce its pressure to under ¼ pound, if this is necessary. (Some services lines carry gas that is already at very low pressure.) This is the normal pressure for natural gas within a household piping system, and is less than the pressure created by a child blowing bubbles through a straw in a glass of milk. When a gas furnace or stove is turned on, the gas pressure is slightly higher than the air pressure, so the gas flows out of the burner and ignites in its familiar clean blue flame.
 

e9999

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I have chain wrench and pipe wrenches and can get more. Tools are not an issue. Any excuse to buy new ones is fine by me...:) But as discussed, twisting is iffy.

There is of course a valve on the main line after the meter. The issue might be any gas left over in the pipe after I relieve the pressure.
 

scottm

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There is of course a valve on the main line after the meter. The issue might be any gas left over in the pipe after I relieve the pressure.
If you have to drain the entire house system, there could be a moderate volume of gas come out. Do you have a gas fireplace where you can let the pressure out?

There needs to be a valve for that line, it could be far from the wall in the middle of the house. It's probably off right now, so you'll have to find it.
 
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so let me get this straight, you have a ng line you think, that you want to use for a grill and you don't know if there's a shut off and the pipe shows signs of corrosion and you have people telling you to use spark generating tools to take the rusty cap off.....you should listen to them and go for it and take some video.


Oh and call the Gas Company and find out how much they love it when people shut off gas lines instead of calling them to do it.
 

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