On 03/03/2021 09:36, Robin wrote:
On 02/03/2021 23:57, Fredxx wrote:

snip

If you know the kW of your boiler you would be able to calculate the
size of pipe you actually need. In domestic situations with limited
pipe runs 22mm copper pipe is a safe bet, plus to save embarrassment
to Gas Safe installer Gas Safe have made a blanket requirement to
combis where they must be piped in 22mm. Though I would be happy to
have the last sectionin 15mm.


I don't want to give false hope to the OP who may well need a new gas pipe.

But I've seen before on some sites that "Gas Safe regulations now state
that gas supply pipes from the meter to a combi boiler must be at least
22mm". Smelt to me like a way to get more work and avoid the bother of
calculating pressure drops.Â* Gas Safe have no power to make regulations.
Â*And while the Gas Safety (Installation and Use) Regulations were
amended in 2018 I can't see anything in them about a minimum pipe size.
Have I missed something?


When our old gas boiler was replaced at our last house the engineer said
he would have to take up the parquet flooring right through the length
of our hall to install a new pipe. We objected telling him to find
another route.

He then agreed to test the gas flow through the old pipe and guess what?
Yes it was more than adequate to feed the new boiler.

Mike