Bore size advice

[cox377]

Hello all,

I’m currently re-plumbing the whole house and getting everything ready for the plumber to commission the boiler.

The water feed into the house currently comes in via lead which is a large pipe but a small bore, about 15mm.

. First fix is in for the all the rads, now I’ve come to the kitchen / bathroom. Bathroom is directly above the kitchen and there is no ceiling so I have full access. At this point there are no pipes in the kitchen / bathroom other than the lead feed

Firstly, should I have a direct feed from the mains in, to the combi boiler, if so would it be 15 or 22mm? The feed would run straight past the toilet basin and bath, I can’t see the advantage of a separate feed as it only starts at about 15mm lead anyway.

The feed into the house seems to have a very decent flow rate however I’ve yet to measure it.

Would I want to feed bath with a hot 22mm from the boiler, considering the feed in is only 15mm?

I’m worried about the shower above the bath having a poor flow rate as the shower would be pulling from the cold feed of the mains and the boiler hot feed, which is also sucking off the code feed. If that makes any sense.

Thank you in advance.

J

 

[Agile]

Cold into the boiler can be in 22mm if the flow rate is marginal.

Hot out should always be in 15mm otherwise it takes a long time to heat up and wastes water and gas.

Flow rate measurements should b a dynamic flow rate. Search if you dont understand that.

Why is the boiler installer not advising you about these matters?

Tony

 

[cox377]

Thank you for your reply Tony.

The boiler installer came over to take a look. He gave me a basic overview of what was required generally before it could be installed and I was pretty confident on what was required. Now I've got to the kitchen that the specifcs are required. I just want to make sure I've got everything clear in my head.

Thanks

J