On 03/03/2021 12:16, Robin wrote:
On 03/03/2021 11:22, bert wrote:
In article , Robin
writes
On 02/03/2021 23:57, Fredxx wrote:

snip
Â*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 pipeÂ* runs 22mm copper pipe is a safe bet, plus to save
embarrassment to GasÂ* Safe installer Gas Safe have made a blanket
requirement to combis whereÂ* they must be piped in 22mm. Though I
would be happy to have the lastÂ* 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?


Only that when combi boilers first appeared a lot of installers used
the existing 15mm which was then found to be inadequate.

Thanks but I was aware of that.Â* And it's a bit of a leap from that to
"you *must* use 22mm even if it's a run of 1.5m with one bend to a 24 kW
combi". Only makes sense to me if Gas Safe members can no longer be
trusted to do sums and measure pressure drops at existing boiler.

On the other hand if you can do the sums, it can only point to you being
more "competent" than the average Gas Safe installer. So possibly a bit
of an own goal