On Wednesday, 4 May 2016 03:04:57 UTC+1, John Rumm wrote:
Gas pipe sizing needs to be worked out for each installation normally,
although there are various rules of thumb that the less clued up fitters
will use in place of doing the actual sums.

"The boiler's got a 15mm inlet so a 15mm pipe will be okay, regardless of kW or length"

Owain