New Boiler question: Worcester or Potterton

Bernard

Not sure if it helps but Bgas have quoted 21metres of 22mm copper pipe to go from the gas meter to boiler location.

southcoastrgi

for starters the WB 24Ri has a 22mm gas connection, the boiler has a max gas rate of 2.6m3/hr, i have just done a quick calulation (although if you provide full details i can work it out more accuratly for you) 21m of 22mm pipework from the meter to the new boiler in a straight run with no bends or any other appliances ie fire, hob etc would give a pressure drop of 1.05mb the max allowed is 1.0mb, so therefore even 22mm is not big enough & a certain amount of pipework from the meter will need to be 28mm & i would also change the meter union to a 1" one, any bends or other things connected to the gas pipe will only make it worse, so for one guy to just say i will connect it to the existing 15mm pipe hasn't worked it out at all & if BG are only going to install 22mm pipe then they are wrong as well.

Bernard

Southcoastrgi, what additional info do I need to provide. I know it will have at least 8 bends as it's got to go around the side wall of the house that has a chimney breast. This pipe would go straight to the boiler. The house does have a gas fire and a gas cooking hob

One of the reasons I might pick Bgas is the quote states 'no nasty surprises ' and 'peace of mind' where it says the price we quote is the price you'll pay and it's a fixed price quotation. So if they have got the pipe work wrong then they would have to correct at no additional cost to me (in theory)!

I feared the Rgi saying try first to see what happens could turn out to be a pointless exercise.

I will ask Bgas to check if 22mm is going to be good enough.

southcoastrgi

ok a rough guide as i can't see it first hand, taking a dedicated pipe straight off of the meter & leaving the other pipework & appliances connected to the existing pipe, total pipe lenght of 21m, first 7m off of the meter 28mm with 4 bends gives a pressure drop of 0.18mb, remaining 14m in 22mm with 4 bends gives a pressure drop of 0.80mb, giving a total pressure drop at the boiler of 0.98mb, you are only allowed a difference of 1mb or less working pressure between the meter & the boiler/appliance, however it's not quite as simply as that because most boilers don't give you a test point before the gas valve so unless the installer puts one in (which they won't) then you can only test from from the gas valve & this will give you some resistance & this is where it gets into a very grey area, the gas regs state no more than 1mb difference however WB say you must have a min of 18.5mb at the inlet test point on the gas valve but if you have 21mb at the meter then 18.5mb won't in theory comply with the gas regs however if you have what the WB says then i would class it as ok.

get Bgas to check but IMO 15mm isn't big enough plus the existing pipe is already connected to the same pipe as your other appliances so no it won't be suitable. & remember when the pressure is tested at the boiler (the existing or the new one) it must be done with all the other appliances switched on & working.

C_Mababejive

Without doing any sums a figure of 21m of 22mm sounds wrong and there will likely be some 28mm involved at the meter end.

Bernard

A small update, which may be useful to other people who have BGas quotes.

Yesterday afternoon a BGas person called from I imagine a contact centre. They stated their role was to call up customers after 8 days if the customer had not signed up to the BGas quote. He basically said he was calling to see if he could improve the quote. Within 1 minute he knocked off another 110 off the price. So I will be going with BGas. I will ask the installation engineer about the pipework size.

Thanks everyone for your input and help.