Well, that was an interesting day. After all that effort sourcing pipe and materials I turn up to the job excited to get started. As soon as the commercial guy turns up, he looks at existing pipe and mine and says, that's too big. This is inch and a quarter and I have inch and a half. Luckily the pipe has play on it and he has fittings on the van.
Then off to look at the meter, the meter does not have a purge point on it. And, there is no chance we can purge job just by air, so need to use nitrogen, but no place to connect it to.
Then were off looking for another plan. Go upstairs and he spots plaque heaters with no ventilation. Says, that's not good. So we ask to look at cp12 of the commercial type. Plaque heaters not listed on it.
So we find an iso valve at kitchen which is inch and a quarter reducing down to 28mm. He says that is your best option. So that gets tee'd into and another valve and test point put in.
I am wondering, from this iso we put in, could I bump the diameter upto 32mm if I needed? As we all know gas compresses.
Oh the joys of being a plumb bum.