May need to disconnect my gas pipework for a bit for safety during building works (gas pipes at risk of damage unless I feel brave enough to cut and blank them off inside the house).
Either way I need to buy a meter cap and washer. Would the size for a typical above-ground domestic meter with a 22mm copper connection more likely be 3/4" or 1" (so I can order the right part from BES)
Or how would 3/4" and 1" translate to an across-the-flats measurement of the union nut (nut that screws onto the meter)?
Can I also just confirm that caps are put on dry without any sealant on the rubber washer.
You want to seal off the meter and everything on the house side of it? What if you shut off the main valve at the meter and remove the handle. Then cut the 22 mm pipe on the domestic side and cap it off at the pipe going to the meter. Leaving the house pipework open to vent any residual gas.
All you have to buy is a 22 mm cap end (stop end). If you want it really gas tight, wrap a couple of turns of PTFE tape around the thread.
You can turn the handle on the valve spigot to face in line with the supply pipe when it's closed, then lock it off with a chain and padlock, or even a plastic zip tie, to the pipe.
BigWallop coughed up some electrons that declared:
Thanks for that. I may at some point want to do some soldering work on the gas pipe, so it should be disconnected from the meter and the meter capped - so I would like to have a cap handy. If they were a quid, I'd buy both sizes, but they're rather more than that.
John Stumbles coughed up some electrons that declared:
I was looking for the discs, but I could only find these:
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"Meter Caps", about 3/4 the way down. These would be fine.
However, I did run a search in BES and located these:
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"Sealing discs" and as you say they are dirt cheap.
Good, thought so, but wise to double check. I'm certainly happy enough to cap off the meter; it's outside so minimal risk. I'll get a manometer whilst I'm at it and have a run though a leak test before I do, just to see how the existing piping is (I may have disturbed the run to the cooker ripping out kitchen units).
Do you feel competant to mess with gas? I'm only asking because halfway through a job you don't want to have to be asking a question on usenet whilst your house slowing fills with gas and eventually explodes.
Well, in that case, I'd throw the isolator valve on the meter and remove the handle :)
This is exactly why I'm looking into it now, before I touch anything. I need to cut off a leg of pipe (cooker feed) and cap it. I have a choice of compression fitting or solder end stop and both are legal as the location is accessible.
I'd rather solder it - but to do that I need to disconnect from the meter and purge the pipe, hence the need for a cap. In the worst case, if I'm not happy with what I've done, after a leak test (manometer and spray) I'll cap the meter and leave it - but I'd rather have the heating available.
Regarding fitting the new boiler next year which will mean all new pipework, I may have found a CORGI fitter who would be willing to check my work under the guise of a gas safety check. As it happens he's trained with Viessmann boilers but he does mostly servicing rather than installations these days, so he's not loosing work as such by such an arrangement.
Re: stopping off a pipe: Yes, I feel happy to do this, not because I know all the answers, but because I know what I need to find out about before I touch anything.
If that worries you, then I'm listening (seriously) but I don't see any issues and I have a fall back if everything goes wrong, which is unlikely.
Whilst I realise it is the right way to do it, I don't think I have seen a corgi cap a meter before soldering a pipe yet (not often seen one use a manometer either!)
John Rumm coughed up some electrons that declared:
It wouldn't surprise me having watched a particular CORGI man in action(!).
But wouldn't it cause a risk of flashback down the pipe and into the meter as after the pipe's cut air will get in? I assumed (in the light of the gas FAQ that disconnecting the pipe and blowing some air though it to dispell the gas might be sensible.
BTW - I found lurking in the back of the meter box a cap. It's metal, looks like 3/4" thread. The 22mm copper is mostly soldered but goes into a compression joint on a brass union that goes onto the meter. Brass union is the bit that the meter's hung by on the bracket.
Looks like the metal cap I found fits the brass union's thread in place of the pipe. The cap looks like it makes a metal-metal joint and has some oil or grease residue inside. This isn't quite what I was expecting.
I think I'm going to wimp out of this, partly because the building's unattended some days (so if there's a problem I won't be there to notice) and I've got builders starting so it's not really fair to cause risk to them, however small.
I did however work out a way to get my money's worth for the call out of a CORGI man. Rather than just requesting a capping off of a leg of pipe expensive at 70-90 quid min call out), I could get him to start a whole new pipe run where I want it, new cooker connection to another room and make a temporary reconnection to the old boiler. That will turn a 20 minute job into a good few hours so makes it a bit more worth it.
A couple of times many years ago, I had a CORGI install gas heaters. On both occasions, the two different fitters completely removed the gas meter whilst installing the pipework. Whilst it was sitting outside on the garden path, I was slightly concerned someone might nick it!
Cool. I was just checking. :) An ex-neighbour of mine burnt his hands after a gas explosion which he was no where near at the time honest gov, and took out half a house.
I wouldn't remove or cap the meter to solder fittings to installation pipework unless I were working right up at the meter itself. You may occasionally get a little pop when unsoldering a fitting on pipework with gas inside it (or applying a light to an open end) it doesn't flash back down the pipework. I think it's because air can't get far down the pipe to sustain combustion.
BTW don't forget your bonding strap if you're cutting installation pipework pipework.
Ed Sirett coughed up some electrons that declared:
Hi Ed,
OK - I was going by the sizes quoted by BES. I wonder if it's referring to the adaptor thingy that's connected to the meter, that forms a compression joint with the pipe - that connection is smaller than the port on the meter.
I did find a cap tucked in the back of the box, that looks like it goes on the adaptor union, rather than the meter port. I'll take a picture next time.
Remind me never to call him. The only thing the guys on site do, is turn on an appliance and light it, and turn off at the main c*ck at the meter. The lit appliance flares off any residual gas in the pipe work. Meters are fitted with gause screens, like you had to put on top of the Bunsen burner stand in school, to stop flare back into the main supply.
Ed Sirett coughed up some electrons that declared:
Ah - so if it looks like a 22mm compression, then it is a 22mm compression thread?
Thanks again Ed. As I mentioned earlier, I think I may back out of this. It's not the soldering that worries me, it's the lack of knowledge about the threaded stuff. It's comparable to me being happy with soldered and compression water fittings, but threaded joints are a mystery. With water, however, on say a pump or tap connector, I can wind on the PTFE or hemp+boss-white[1] until it stops dripping - not something I think I should experiment with. I'll stick with the electrics - of that I am fully confident.
Maybe later, when I'm not under pressure from other jobs ;-> Perhaps also if I'm in a position of having a CORGI "supervisor" should one be forthcoming.
[1] Yes, I know about potable restrictions on hemp/boss-white - I was being nostalgic.
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