Gas supply issues for new Combi Boiler

15 Feb 2012
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United Kingdom
I desperately need some help and advice.

My combi boiler has recently packed up and I need to replace it. I have decided to have a Worcester Greenstar 37CDi fitted.

Before I do I have a problem with my gas supply. My gas meter is 53m from my house, connected by a 28mm pipe. I have been advised that the current 28mm pipe will not deliver the required working pressure for a modern combi boiler because of the pressure drop over such a long pipe length. Apparently the maximum pipe length for a 28mm pipe to deliver the right working pressure is 40m.

I have been advised that the only solution certain to resolve the problem is to move the meter closer to the house. It has been suggested to me that leaving the meter where it is and replacing the current 28mm pipe with a thicker one might work but nobody seems to be sure.

I have contacted Northern Gas Networks and sent them a diagram. In their response they have indicated that not only will they need to replace the 53m of pipe on my property but also the 6m of pipe under a public highway from the gas main under the road to my property's boundary (where the meter is currently cited). They are proposing to fit a 63mm PE LP service for the total 59m length.

The problem I have is the cost. They have provided me with 2 options: 1) £5800 for them to do everything, and 2) £3500 for them to replace the 6m of pipe under the public highway and fit the 53m pipe where I have organised the excavation of an open trench or appropriate duct.

Where I need the advice is as follows. I don't have a problem paying to upgrade the 53m of pipe on my land. However, I don't see why I should have to pay for the upgrading of the 6m of pipe under the public highway, which accounts for £3500 of the total cost. To me if the pipe under the public highway is the limiting factor in delivering the required working pressure for a modern combi boiler then surely the supply directly from the gas main is not fit for purpose, so I don't see why I should pay for this upgrade.

Am I missing something? I would welcome any advice. If anybody knows anybody I can speak to about this I would be very grateful.

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If the installation was existing then you might have an argument. As you are doing this as a project they can pretty much charge what they like.
The simple solution is to install a system boiler and unvented cylinder
you then wont need to do anything with your gas pipe and will have better
water delivery.
I am surprised your plumber didnt suggest it
if your are anywhere near doncaster i can sort you out
send a personal message
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Its times like that make ya want to be self sufficeint , solar thermal/pv ect and fook the utility companys off.
Makes you wonder why the OP has decided upon the boiler?

maybe customer decided that was boiler he wanted and plumber
didnt question the choice
53m is quite a distance just curious to see the arrangement of the
propertyand why the meter is so far away.
Which leads me to wonder if it is a suitable boiler.

Can't be a7sed to work lengths and pressure dops tonight, but domestic installers can do 32mm now. Pricey... but.?
Yep 35mm will do the job (60 odd KW) , although IGE/UP1a will apply (commercial ticket).
We've recently put 60m of 63mm down someones drive.

They were having a 40cdi and there was a large range cooker too.

Cost wise, It is all down to the material you have to cut the trench into, a grass or gravel route is always easy for groundworks people on a digger. Our groundworks subbie cut it out and reinstated in a day.

I would expect, in most scenarios, this would be the cheapest route, upsize your own pipe and keep the meter where it is. As stated, the pipe would need to be installed under the commercial gas routine (very different procedure to domestic), so you would need to use a gas chap with that ticket.

The option of unvented if you have the space is the best route.

Regarding your original question, the pipe sizing and engineering solution chosen by your supplier is their call, and you have no say in the matter. You have three options, unvented, replace your pipe, move the meter. I've listed them in terms of cost.

We dont cover anywhere near Yorkshire but the costings from the gas supplier dont seem unreasonable. When i wanted mains gas here in Kent it was quoted at £42000.
Unvented OR Thermal Store

I can fix a combi myself ( thats my job) , but that dosent mean I'd have one in my own house.............. ;)
Have you compared the gas rates of the old and new boilers?

As long as the rate and inlet pressure at the multifunctional gas valve in the boiler are correct, it should be OK. Manufacturer's spec overrides all else!
You've lost me there. If the new boiler has a higher gas rate then the pressure drop is likely to raise.

What I find surprising is the '28mm' pipe scenario. It would be uncommon for a copper pipe to be buried over this distance, it would normally be steel or PE.
If the gas rate is the same, which it may be, the existing pipework may be OK.

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