Low gas pressure at boiler

10 Nov 2016
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United Kingdom
Hi, our gas boiler was moved when we had an extension built and the gas supply pipe is now at least 20m from the meter with many bends. It's time to replace the boiler but my plumber says the gas pressure at the boiler is way too low (I think he said 13?) and advises sorting this out before getting a new boiler, which I want to do. What do I do about getting the pressure increased? The gas pipe from the meter to the original boiler position is buried under the house somewhere. The extension to the gas pipe is visible. It looks about 16mm diameter. It might be possible to run a new, larger diameter gas pipe around the outside of the house. Would an upgrade to the meter help?

Can anyone suggest from my description roughly what the solution is, and who I need to contact for more advice? It's a 5 bedroom house so ideally we need a bigger boiler. We also have a gas hob and a gas coal-effect fire.

I have spoken to a couple of companies who upgrade supplies and meters, but they can only carry out the work I request, and not advise me what needs to be done. Any pointers in the right direction would be very welcome. I'm in Wiltshire. Thanks
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So you're saying that the boiler is approx 20m from the meter? What size boiler is existing? If the gas pressure is low at the boiler, it indicates undersized pipework.... sounds like your guy is suggesting the right thing, especially if u are increasing the boiler size.
no modern combi will be correctly gassed off 20m of 15mm pipe..Even 22mm could be pushing it on many combi's
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With no information on your house we can only guess.

But a starting point would be to know what power your existing boiler is.

A modern five bed house would usually need a boiler of 15-20 kW to include 2 kW for water heating.

An old solid wall house with good loft insulation could be say 20-25 kW.

A 24 kW heat only boiler would usually need about half of the 20 m run in 28 mm, possibly more than half. Depends on the number of bends and where the other gas appliances are connected.

If everything at the back of house then probably 28 mm all the way to the back!

Could go round the outside of the house in most cases.


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