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Yes. They get discussed here from time to time.

 

A solution looking for a problem. They only work with a major loss of downstream pressure. How many major gas leaks have you suffered in your boating career?

 

51w-mUg7u6L._SY355_.jpg

I see your point, but one major leak is all you are ever likely to experience, so to speak? My toaster has never gone "live" but I have an RCD on the dis. board should that ever happen.

I always think about LPG finding its way into bilges, and how dangerous and difficult it can be to remove.

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I think what these are intended for (catastrophic break of a pipe) is unlikely on a boat with no-one around... bilges tend to fill from slow leaks which this won't prevent and is why the recommendation is to turn off at the bottle(s) when not in use... although I am sure many don't even do that ... They can't be a bad idea to have though ...

 

Nick

Edited by Nickhlx
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I think what these are intended for (catastrophic break of a pipe) is unlikely on a boat with no-one around... bilges tend to fill from slow leaks which this won't prevent and is why the recommendation is to turn off at the bottle(s) when not in use... although I am sure many don't even do that ... They can't be a bad idea to have though ...

 

Nick

I can see that slow leaks are a more likely problem. I suppose the bubble tester is a more likely contender?

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I can see that slow leaks are a more likely problem. I suppose the bubble tester is a more likely contender?

 

 

Sadly, no.

 

Bubble testers are fine in principle but they are rendered effectively useless by the stupid BSS rule governing where they must be installed. If they could be fitted in a convenient, visible and accessible position people might use them regularly. But the BSS demands they are fitted out of sight and out of mind, in a hard-to-see, hard-to-use location inside the gas locker. So they only get used once every four years during a BSS inspection.

 

Hands up who has a bubble tester in their gas locker, and they DO use it on, say, a weekly or more frequent basis...

 

 

MtB

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Sadly, no.

 

Bubble testers are fine in principle but they are rendered effectively useless by the stupid BSS rule governing where they must be installed. If they could be fitted in a convenient, visible and accessible position people might use them regularly. But the BSS demands they are fitted out of sight and out of mind, in a hard-to-see, hard-to-use location inside the gas locker. So they only get used once every four years during a BSS inspection.

 

Hands up who has a bubble tester in their gas locker, and they DO use it on, say, a weekly or more frequent basis...

 

 

MtB

 

Mike

 

Funny you should say that!! On my recently aquired boat in the gas locker is an amazingly easy to see and get at changeover system from one cylinder to the other ( gas locker not in pointy end thank god ) very accesible. It has a see through sort of sight glass built in to the top of it which I think is some sort of bubble tester? it doesnt push or move or anything, just what is it please?

 

Tim

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Sadly, no.

 

Bubble testers are fine in principle but they are rendered effectively useless by the stupid BSS rule governing where they must be installed. If they could be fitted in a convenient, visible and accessible position people might use them regularly. But the BSS demands they are fitted out of sight and out of mind, in a hard-to-see, hard-to-use location inside the gas locker. So they only get used once every four years during a BSS inspection.

 

Hands up who has a bubble tester in their gas locker, and they DO use it on, say, a weekly or more frequent basis...

 

 

MtB

I see. I don't have a bubble tester and have wondered about fitting one, but as you say, I would only remember to use it at Safety Test time, or perhaps when changing a gas bottle rolleyes.gif

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Sounds like it might be a bubble tester. Does it look like this?

 

307956.jpg

 

Hi Mike

 

No it doesnt look like that. Im hopeless at fotos and still cannot post on here, Ive never been to uni to take the degree course required to work it out. It has a white plastic knob which has a red arrow on that seems to point to the gas cylinder it detects as having gas coming from it and two pigs tails one for each cylinder but mounted on the top of the valve body thingy is this see through bit, it looks a bit like an inverted sewing thimble and about same size? blink.png

 

Tim

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I think all bulk gas tanks at e.g. remote houses who can't get mains gas supplied, have these as a matter of course...

 

Nick

 

There's also a "slam shut" valve built into mains gas meters, which performs the same function.Can be a bit of a pain if the gas has been turned off for a while ...

 

Iain

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I bought one last summer, but could not get it to seal effectively at the bottle end.

 

So it has gone into my newly tidied collection of "stuff" (now sorted into four small plastic crates...).

 

Ahh "collection of stuff" all over my boat, in different places, in different containers...

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There's also a "slam shut" valve built into mains gas meters, which performs the same function.Can be a bit of a pain if the gas has been turned off for a while ...

 

Iain

 

News to me! I've never heard of a domestic gas meter with one. Is this meters on commercial supplies perhaps?

 

High gas flow rates are needed when purging so I'm reasonably sure this would have been mentioned during our training if they existed in domestic gas meters, as a slam shut valve would be a confounded nuisance.

 

MtB

I bought one last summer, but could not get it to seal effectively at the bottle end.

 

So it has gone into my newly tidied collection of "stuff" (now sorted into four small plastic crates...).

 

I notice in the photo there is an O ring let into the end of the pol connector. Maybe yours is missing.

 

MtB

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From the link in the OP:

 

 

But the BSS allows zero loss of pressure. I haven't heard of a 70% fail on gas inspections.

interesting point.

 

The BSS checklist requires testing to determine gas tightness which shall show there are no leaks when tested in accordance with the appropriate testing procedure. And as MtB has often pointed out, a bubble tester does not prove 100% gas tightness. The assumption that gas tightness criteria is zero loss of pressure is not actually valid, and certainly is not directly demonstrated by a bubble tester which does not measure pressure or drop in pressure..

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The thing is, no gas system can ever be totally gas tight. A few molecules here and there are bound to escape though joints, fittings, and especially the on/off valves in appliances, and the tightness test procedures are designed to accommodate this.

 

The 70% quote is disingenuous though. It give the impression that 70% of installations would fail a tightness test, when the requirement is that none fails a tightness test.

 

 

MtB

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There's certainly a slam shut on our domestic meter.

Caught me out when the gas fire was re-instated a good few years ago, and since then I've come across a few other domestic ones which have operated, usually after the gas has been switched off for a while.

 

Iain

Edited by Iain_S
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There's certainly one on our domestic meter.

Caught me out when the gas fire was re-instated a good few years ago, and since then I've come across a few other domestic ones which have operated, usually after the gas has been switched off for a while.

 

Iain

 

Intriguing. Is yours an ordinary U6 meter?

 

MtB

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There's also a "slam shut" valve built into mains gas meters, which performs the same function.Can be a bit of a pain if the gas has been turned off for a while ...

 

Iain

 

 

Not for most of the uk there is not.

If the inlet pressure on your main supply exceeds 75 mbar (ie medium pressure or higher) then there will be one. This usually means you live out in the sticks as nearly everyone has low pressure mains gas.

Edited by mark99
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I bought one last summer, but could not get it to seal effectively at the bottle end.

 

So it has gone into my newly tidied collection of "stuff" (now sorted into four small plastic crates...).

 

I notice in the photo there is an O ring let into the end of the pol connector. Maybe yours is missing.

 

MtB

 

Thanks - but it is present. See earlier thread (and blurry photo) here - you commented then as well on the importance of O rings.

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The thing is, no gas system can ever be totally gas tight. A few molecules here and there are bound to escape though joints, fittings, and especially the on/off valves in appliances, and the tightness test procedures are designed to accommodate this.

 

The 70% quote is disingenuous though. It give the impression that 70% of installations would fail a tightness test, when the requirement is that none fails a tightness test.

 

 

MtB

Pretty much waht our boat safety man says. He claims gas cookers are a common source of such leaks.

 

Interesting comments re these units and bubble testers. Think I shall carry on without them.

Edited by Guest
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Intriguing. Is yours an ordinary U6 meter?

 

MtB

 

Not sure of meter type. They seem to be quite common around here, as when we had our CH boiler replaced recently, the plumber knew exactly where to look. I thoght they were standard; maybe it was a Scottish Gas thing ....

 

Iain

 

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Edited to add picture of meter. Valve is top left .

Edited by Iain_S
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