Boiler puzzler

[DJTINO]

So there I was all set to have a boiler installed until it was identified that I hsve a 15 mm.gas pipe. DUH DUH DUHHHHHHH....

Don't fancy having to lift up all my floorboards for a pipe upgrade but I may have to. Have heard that Vailants run on 15mm - but only on a short pipe run (my distance from meter to boiler is at least 30ft). Is there any point in me getting an engineer up to conduct a pressure drop.test given this info? Unless there is another boiler will would work on this basis (doubtful).

Any advice appreciated. Cheers.

 

[oldbuffer]

1. Required size of gas pipe depends on boiler output. Only the smallest likely to work correctly on 15mm pipe over the 10 metre run.
2. Highly unlikely ANY combi boiler will run on 15mm pipe.
3. A very small (15 / 18 kW) open vent boiler might run.
4. The deciding factor is the pressure drop between meter and boiler with the boiler running flat out. Maximum allowed is 1 milli bar.
5. Each fitting in a pipe run "counts" as an additional run of pipe. Elbows and tees equivalent to 0.5 metres, 45's and gentle bends equivalent to around 0.3 metres.
6. It is possible to use combinations of diameters to achieve and acceptable drop. May be 22mm pipe for the first 7 metres then 15mm pipe for the rest.
7. Additional gas using appliances also have to be allowed for.
8. A Gas Safe registered engineer can do the calculation provided he / she can derive the actual pipe run and number / type of fittings.
9. You can't do a pressure drop test without the boiler in place, by which time it is too late.
10. You should be able to look at the pressure drop with an existing, working, boiler in place, and can reasonably extrapolate whether the pipework will support a ightly larger capacity boiler.

 

[DJTINO]

Many thanks for that. I think point 10 would be the best guideline then as I have a boiler (old as it is) working on 15 mm currently. No other gas appliances in property so rather hoped that might work in my favour a bit

 

[CountryFan]

Could it be ran externally?

 

[DJTINO]

Could it be ran externally?

Sadly, no as I am in a terraced building with neighbours either side. I am wondering internally, though, perhaps along ceilings with trunking.

 

[CountryFan]

Sadly, no as I am in a terraced building with neighbours either side. I am wondering internally, though, perhaps along ceilings with trunking.

We lived in a terraced house. Gas pipe went up from lounge, passed front bedroom into loft and then down into rear bedroom to feed the boiler.

 

[DJTINO]

We lived in a terraced house. Gas pipe went up from lounge, passed front bedroom into loft and then down into rear bedroom to feed the boiler.

Thanks anyway, but I am on the ground floor with no loft and have another property above me.
I was hoping SGN might relocate my meter closer to the boiler at an affordable price but they want £4,200 up front for this 'alteration'.