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  • FIRST POST
    • Tom The Great Sebastian
    • By Tom The Great Sebastian 9th Jun 17, 5:03 PM
    • 813Posts
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    Tom The Great Sebastian
    Gas pipe camera inspection ?
    • #1
    • 9th Jun 17, 5:03 PM
    Gas pipe camera inspection ? 9th Jun 17 at 5:03 PM
    Long story short.
    Built house.Originally laid 3/4" gas pipe under concrete.
    Come to hook up the boiler and not enough pressure to fire it up.Engineer suggests kink or blockage in pipe. We're going to try air compressor to blast out the pipe with air but ....

    Question: Is there the technology available to put a camera down the 3/4" pipe to detect anything before having to drill everything up and lay again.Can I hire someone to come and do this ?

    Thanks in advance.
Page 1
    • FreeBear
    • By FreeBear 10th Jun 17, 1:06 PM
    • 1,102 Posts
    • 1,628 Thanks
    FreeBear
    • #2
    • 10th Jun 17, 1:06 PM
    • #2
    • 10th Jun 17, 1:06 PM
    You can get cameras for inspecting pipes internally - A company close to me makes pipeline cameras for the oil & gas industry (mega bucks)..

    For a small pipe, assuming a straight run, a cheap endoscope from ebay would probably do the job. https://www.ebay.co.uk/sch/i.html?_nkw=10m+usb+endoscope
    Her courage will change the world.

    Treasure the moments that you have. Savour them for as long as you can for they will never come back again.
    • DaftyDuck
    • By DaftyDuck 10th Jun 17, 1:26 PM
    • 3,575 Posts
    • 7,144 Thanks
    DaftyDuck
    • #3
    • 10th Jun 17, 1:26 PM
    • #3
    • 10th Jun 17, 1:26 PM
    Replace pipe! Kink or bend under concrete equals weakened pipe. Gas pipe, too. Under concrete!!! Few more!!!! for emphasis.

    Even if it is semi-sorted for now, it will fail later.

    Get pipe replaced.

    Oh, it was properly covered to protect it from the concrete, wasn't it?
    • Furts
    • By Furts 11th Jun 17, 6:02 AM
    • 3,249 Posts
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    Furts
    • #4
    • 11th Jun 17, 6:02 AM
    • #4
    • 11th Jun 17, 6:02 AM
    I second DaftyDuck. Over the years I have been told do not put gas pipes in floor slabs, nor duct them under, or through, concrete slabs.

    A new pipe seems the proper way forward to me.
    • southcoastrgi
    • By southcoastrgi 11th Jun 17, 1:50 PM
    • 5,167 Posts
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    southcoastrgi
    • #5
    • 11th Jun 17, 1:50 PM
    • #5
    • 11th Jun 17, 1:50 PM
    3/4 or 22mm ?
    The pipe might not be big enough for the boiler anyway
    It would have to be really kinked or damaged to not let the boiler fire at all
    I'm only here while I wait for Corrie to start.

    You get no BS from me & if I think you are wrong I WILL tell you.
    • Tom The Great Sebastian
    • By Tom The Great Sebastian 12th Jun 17, 4:58 AM
    • 813 Posts
    • 924 Thanks
    Tom The Great Sebastian
    • #6
    • 12th Jun 17, 4:58 AM
    • #6
    • 12th Jun 17, 4:58 AM
    I second DaftyDuck. Over the years I have been told do not put gas pipes in floor slabs, nor duct them under, or through, concrete slabs.

    A new pipe seems the proper way forward to me.
    Originally posted by Furts
    How else are you supposed to lay a gas pipe under a house from street meter to boiler ?
    It's standard practice here in Ireland to lay pipe in a new build between the insulation and poured concrete floor.
    It's a 3/4" copper pipe in white plastic casing which is industry standard.
    The pipe was clipped down onto insulation boards before the concrete was poured.
    We find it hard to believe there's an obstruction or link because of the care we took and also because when one person blows down one end of the 50 foot pipe it's possible to feel the air coming out of the other end.

    Anyway the compressed air has produced nothing so camera is the next option.
    The pipe is drawing 20 bars of pressure but when the boiler attempts to kick in this instantly drops to 10.
    That and getting the new meter checked by the gas board appear to be our only options other than laying a new pipe which is going to be hugely problematic because the house build has been completed.
    • Le_Kirk
    • By Le_Kirk 12th Jun 17, 9:48 AM
    • 1,791 Posts
    • 893 Thanks
    Le_Kirk
    • #7
    • 12th Jun 17, 9:48 AM
    • #7
    • 12th Jun 17, 9:48 AM
    Maybe it is the distance from supply point to boiler that is the issue and the pipe is not big enough!
    • firefox1956
    • By firefox1956 12th Jun 17, 10:21 AM
    • 1,037 Posts
    • 571 Thanks
    firefox1956
    • #8
    • 12th Jun 17, 10:21 AM
    • #8
    • 12th Jun 17, 10:21 AM
    It sounds to me as though your problem might NOT be your pipe.
    As you say it would nearly have to be squashed flat to be that restricted &
    if you laid the pipe yourself you would have noticed a kink that bad.
    Sounds to me more like a problem at the meter or the boiler.
    I would be investigating at either end before starting ripping floors up !!
    HTH
    • ComicGeek
    • By ComicGeek 12th Jun 17, 10:57 AM
    • 144 Posts
    • 97 Thanks
    ComicGeek
    • #9
    • 12th Jun 17, 10:57 AM
    • #9
    • 12th Jun 17, 10:57 AM
    How else are you supposed to lay a gas pipe under a house from street meter to boiler ?
    It's standard practice here in Ireland to lay pipe in a new build between the insulation and poured concrete floor.
    It's a 3/4" copper pipe in white plastic casing which is industry standard.
    The pipe was clipped down onto insulation boards before the concrete was poured.
    We find it hard to believe there's an obstruction or link because of the care we took and also because when one person blows down one end of the 50 foot pipe it's possible to feel the air coming out of the other end.

    Anyway the compressed air has produced nothing so camera is the next option.
    The pipe is drawing 20 bars of pressure but when the boiler attempts to kick in this instantly drops to 10.
    That and getting the new meter checked by the gas board appear to be our only options other than laying a new pipe which is going to be hugely problematic because the house build has been completed.
    Originally posted by Tom The Great Sebastian
    It is commonplace to run the gas pipe in screed above insulation as you have done - I think the previous posters were concerned that it had been laid in a concrete slab without protection, which would have been an issue.

    When you say 20 bars of pressure, I assume this is actually mbars? More likely that the installed pipe is damaged somehow, as 50 foot pipe for a large 38kW combi in a 22mm copper pipe with a couple of bends would probably only be about 2 mbar loss, not 10 mbar.

    Still very close to the limit though as some boiler will need 18mbar or higher to work. I would definitely have used 28mm pipe instead of 22mm, with a loss of less than 1mbar. Personally I think you need to look at options for running a new gas pipe internally (with suitable ventilation in voids).
    • ComicGeek
    • By ComicGeek 12th Jun 17, 11:06 AM
    • 144 Posts
    • 97 Thanks
    ComicGeek
    Actually, just looking at the figures again, are you 100% it wasn't 15mm copper pipe, not 22mm. I've just done a rough calc with 50 ft 15mm copper on a 38kW combi, and come up with a pressure drop of 10 mbar......
    • Tom The Great Sebastian
    • By Tom The Great Sebastian 12th Jun 17, 2:42 PM
    • 813 Posts
    • 924 Thanks
    Tom The Great Sebastian
    Definitely 3/4"
    • Alex1983
    • By Alex1983 12th Jun 17, 3:40 PM
    • 270 Posts
    • 142 Thanks
    Alex1983
    Where are you testing the inlet pressure from, if using p1 on the gas valve you could lose up to 3mb though the gas vavle. Try getting a test point put into the pipework and get tested again, also what is the meter inlet pressure when the boiler attempts to fire.

    I'd would think the boiler would still fire even at that low pressure but baffle out or not reactifiy, what size boiler do you have and do you have any other gas appliances such as a hob you could test from.

    As others have suggested if the boiler is over 30kw it's likely the gas pipe is under sized.
    • Furts
    • By Furts 12th Jun 17, 8:14 PM
    • 3,249 Posts
    • 2,051 Thanks
    Furts
    It is commonplace to run the gas pipe in screed above insulation as you have done - I think the previous posters were concerned that it had been laid in a concrete slab without protection, which would have been an issue.
    Originally posted by ComicGeek
    But OP has said the gas pipe is buried in the insulation under the "poured concrete floor". No mention of a floor screed.
    • ComicGeek
    • By ComicGeek 12th Jun 17, 9:15 PM
    • 144 Posts
    • 97 Thanks
    ComicGeek
    But OP has said the gas pipe is buried in the insulation under the "poured concrete floor". No mention of a floor screed.
    Originally posted by Furts

    You're right, but not the first time I've heard concrete screed described as concrete floor - I was just hoping that the poured concrete floor was the screed, and giving the OP some credit. The OP mentions clipping on top of the insulation boards, which would normally be above any concrete slab or beam/block flooring in a domestic scenario - very rare to have insulation below the concrete slab with residential loadings.
    • Tom The Great Sebastian
    • By Tom The Great Sebastian 12th Jun 17, 11:34 PM
    • 813 Posts
    • 924 Thanks
    Tom The Great Sebastian
    You're right, but not the first time I've heard concrete screed described as concrete floor - I was just hoping that the poured concrete floor was the screed, and giving the OP some credit. The OP mentions clipping on top of the insulation boards, which would normally be above any concrete slab or beam/block flooring in a domestic scenario - very rare to have insulation below the concrete slab with residential loadings.
    Originally posted by ComicGeek
    You're right.
    I was referring to poured concrete as screed which goes over insulated boards with the gas pipe clipped to this and which are themselves over a gravel-type base on bare earth.
    Anyway,a bit of a result tonight.It seems the compressed air must have done something because after connecting everything back up the boiler fired first time and is now running normally.
    We're not quite sure what has changed - possibly something that got into the pipe which has been moved.
    Either way it's a huge relief.
    Thanks to everyone who came up with advice and suggestions.
    MSE at its finest.
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