Re-run gas supply to boiler - options

[danieljamesscott]

Hi,

We live in a listed building, so are restricted in what we're allowed to do with regards to new pipework, etc.

We have a minor issue in that there's a slight drop in gas pressure between the meter and the boiler. We had a plumber round recently to fix a water leak who was a little concerned about it, but determined that it was OK in the end. I'd like to get some ideas/options incase there's a further drop in the future, or the regulations change and the drop is deemed 'unsafe' by new regulations.

The pipe comes from the meter, and disappears into a concrete floor, and somehow re-emerges from the floor 3-4m away in another room. There's a big chimney directly in the way and I'm assuming that the pipe goes around this, through the floor, although I'm not sure.

When it emerges from the floor, it makes a sharp 90 degree bend, and goes through a brick wall (another chimney), inside the chimney, it makes two further 90 degree bends and comes back through the chimney wall, and then up to the boiler. In the past, the boiler used to be in the chimney, and when it was moved up on the wall, the fitter couldn't get close enough to make a clean cut/join where the pipe emerges from the floor, so routed it back through the wall.

Anyway, I'd like to know what options I have just in case there are issues in the future:

1. What are the likely causes of the pressure drop? The bends in the pipe? Debris in the pipe?
2. Is it possible to have the pipe cleaned/checked to see if there are any obstructions?
3. Is it possible to re-run a new pipe along the same route as the existing one, given that it's buried in the floor?
4. Is it difficult/complicated to remove the 'kink' where the pipe doubles back through the chimney wall. The issue seems to be the cast iron pipe which is close to the floor and in a corner.
5. Is there any solution where we could 'burrow' a new pipe under an existing floor? We have water based under floor heating in one room, so it would be nice not to have to pull it up.

Sorry for the monster post!

Thanks,

Dan

P.S. In case anyone wonders, I won't be doing any work myself. I don't touch gas!

 

[ianmcd]

All depends what the drop is and which boiler you have and any other gas appliances

 

[AGAS]

a few pictures of what you have got would help ? and what ian has said above .

 

[danieljamesscott]

OK, thanks. I have a Vaillant boiler: "ecotec plus 618 18kw system boiler". No other gas appliances. The pressure drop is 2-3mbar - around 19 at the meter, and 17 at the boiler.

Picture attached. You can just about make out the white cast iron pipe coming from the floor, and the copper above it which goes up into the boiler. The copper is covered by the wood/plasterboard inside the chimney.

(The other two pipes are condensate/pressure release from the boiler. Unfortunately they had to go around the chimney to get to the outside.)

 

[Agile]

The pressure at the meter is meant to be 21 mbar +/- 2 mbar.

If the meter was adjusted to the correct 21 mbar or better still 23 mbar then the pressure at the boiler would become 19 mbar or more.

But the boiler will work fine at 17 mbar although the maximum allowed pressure loss is only 1 mbar between meter and boiler.

You don't seem to realise that the pressure loss is due to the natural resistance of the gas flowing through the pipe.

The pipe can be replaced but you will face significant physical problems doing it and will see no benefit at all.

Better leave it as it is.

Tony

 

[danieljamesscott]

The pressure at the meter is meant to be 21 mbar +/- 2 mbar.

If the meter was adjusted to the correct 21 mbar or better still 23 mbar then the pressure at the boiler would become 19 mbar or more.

But the boiler will work fine at 17 mbar although the maximum allowed pressure loss is only 1 mbar between meter and boiler.

You don't seem to realise that the pressure loss is due to the natural resistance of the gas flowing through the pipe.

The pipe can be replaced but you will face significant physical problems doing it and will see no benefit at all.

Better leave it as it is.

Tony

Thanks for the reply.

Of course I understand that there will be some drop due to the resistance in the pipe, as I said above, my concern is that the regulations change, or the pressure drops further for some reason and my existing installation is then deemed 'unsafe'. The engineer we had round recently was quoting loads of recent standards and our existing installation is out of compliance (he did seem like a 'worry wart' and was pointing out lots of things, even though we've had 2-3 other plumbers round for safety checks, etc, who didn't notice any issues). I see that it's fine for now, but I'm worried that at some point, we'll need to have some work done for some reason (new meter, for example) and then we'll need to have this issue corrected, to bring it up to current standards. I'd like to be prepared for this, so that we have some options ready, just in case.

 

[PullerGas]

The pressure at the meter is meant to be 21 mbar +/- 2 mbar.

If the meter was adjusted to the correct 21 mbar or better still 23 mbar then the pressure at the boiler would become 19 mbar or more.

But the boiler will work fine at 17 mbar although the maximum allowed pressure loss is only 1 mbar between meter and boiler.

You don't seem to realise that the pressure loss is due to the natural resistance of the gas flowing through the pipe.

The pipe can be replaced but you will face significant physical problems doing it and will see no benefit at all.

Better leave it as it is.

Tony

I guess he could get an RGI to increase the size of the visible gas pipe from the meter to where it disappears into the floor, whatcha think Tony??
Me I'd 'have a wee look' at the regulator on the gas meter..........

 

[snes]

I can't believe there isn't a better way to route those 2 pipes that go right across your fire opening. Not exactly a pretty site.

 

[ServiceNumpty]

Newly laid floor with UFH as well. Was there no way those pipes could have been run in the screed?

 

[PullerGas]

Ah, it's MI under the screed it'll be rotted to buggery anyway!!

 

[bernardgreen]

We live in a listed building,

So do I, it can be interesting when repairs, maintainance or "improvements" are involved.

so are restricted in what we're allowed to do with regards to new pipework, etc.

Most Conservation Officers will accept that there has to be a compromise between preserving "historical fabric" and ensuring the building remains fit for purpose.

If it is found necessary to install new gas pipework then the Conservation Office should allow it to be installed. It may take a few days of conversation to convince them of the need and to reach agreement on the routing of the pipe work. Making the installation safer and thus reducing the risk of fire damage to the property is a strong point with some Conservation Officers.

 

[Dan Robinson]

I think the RGI should be reading the manual for the boiler a bit more closely .

 

[PullerGas]

We live in a listed building,

So do I, it can be interesting when repairs, maintainance or "improvements" are involved.

so are restricted in what we're allowed to do with regards to new pipework, etc.

Most Conservation Officers will accept that there has to be a compromise between preserving "historical fabric" and ensuring the building remains fit for purpose.

If it is found necessary to install new gas pipework then the Conservation Office should allow it to be installed. It may take a few days of conversation to convince them of the need and to reach agreement on the routing of the pipe work. Making the installation safer and thus reducing the risk of fire damage to the property is a strong point with some Conservation Officers.

Your Shed has had its gas meter altered by its owner BG, so has no insurance cover!!

 

[PullerGas]

I think the RGI should be reading the manual for the boiler a bit more closely .

Oh it's as rough as buggery Dan.

 

[bernardgreen]

Your Shed has had its gas meter altered by its owner BG, so has no insurance cover!!

Get your facts right before spouting your garbage riddled comments