Boiler advice needed please

NRGMAN

Many thanks, Albermarle and FreeBear. I will report back tomorrow once the engineer has visited and advised me on the best course of action.

I have a strong feeling that one of his considerations will be external 22 inch pipework, but that notion will immediately be abandoned when he sees the layout of the terraced building as this pipework would go round the building and cut across my next-door neighbour's property! The other, undoubtedly a heat-only boiler with an unvented cylinder, which seems more realistic and practical. Unless, of course, he plays a blinder with another solution unbeknownst to me….

FreeBear

I have a strong feeling that one of his considerations will be external 22 inch pipework

22 INCH - What are you running, a small gas fired power station 🤣 🤣

NRGMAN

https://forums.moneysavingexpert.com/discussion/comment/82112616#Comment_82112616

Whoops!!! 😂 My apologies. 22 mm pipework that should have been, obviously. 😁

Well, gas engineer came out today as arranged. He surprised me with what he felt would be the best course of action for me with the least disruption and also the most affordable option. And this is to arrange for SGN to carry out an "alteration" (i.e. relocate the gas meter from the front to the rear of the property). He will then take care of everything else from there.

molerat

And the £K quote from SGN is ? Is the possible 6 to 12 week lead time acceptable ?

FreeBear

https://forums.moneysavingexpert.com/discussion/comment/82113637#Comment_82113637

Google suggests £500 to £1200 +VAT - Likely to be the upper end. May also need permission from the freeholder and they would probably want a fee to process the paperwork.

jimi_man

In my last house when I had an old boiler replaced, it was 15mm pipework into the boiler and the engineer said we'd need 22mm now. It was a heat only boiler. Fortunately it was 22mm under the floor to the kitchen then down to 15mm from that up from the kitchen floor so it was straightforward.

The point being that it didn't matter that it was a heat only boiler, it apparently had to be 22mm.

NRGMAN

molerat I'll get more details on Thursday hopefully as a fella from SGN is coming out then to survey the locations so I will get timescales and costs clarified with him. If these are agreeable, then, fine, I'll go for it. Failing that, I'm not sure what I'll do as the experience of jimi_man has stunned me to be quite honest. Unless that's what that particular engineer insisted upon but, from what I read elsewhere anyway, 15 mm pipework is adequate for heat-only boilers. Maybe depends on the choice of boiler.

FreeBear

It really depends on the amount of gas a new boiler needs. A 12kW heat only may be fine on 15mm depending on the length (and the number of bends/elbows). You might even get away with a 30kW boiler on 15mm if the pipe is short enough.

As said before, there are some fairly simple calculations that you could do. One example → https://registeredgasengineer.co.uk/technical/low-pressure-and-under-sized-pipework/

There are other documents out there that explain how to calculate size & length. You might even find an online calculator.

jimi_man

https://forums.moneysavingexpert.com/discussion/comment/82114773#Comment_82114773

From memory, it may have been due to the length (10 metres or so), the fact that it supplied a gas cooker as well, and that it was (I think) a 28kwh Vaillant or something close to that. So maybe that had something to do with it. May also have been something in the Manufacturers Instructions, I can't remember exactly. We had so many issues with the Vaillant that I've tried to eradicate it from my mind! It only lasted 9 years. (We replaced it with a WB which was faultless).

I just recall him saying that I needed 22mm gas pipework now but he didn't specify why and tbh I didn't ask him. So you may be ok with what you have.

Albermarle

https://forums.moneysavingexpert.com/discussion/comment/82115188#Comment_82115188

I just recall him saying that I needed 22mm gas pipework now but he didn't specify why and tbh I didn't ask him. So you may be ok with what you have.

From my experience with heating engineers, you can get many different answers from different ones.