pipe run advice

22 Aug 2009
Reaction score
United Kingdom
just a bit of advice please. I am getting my old mains lead pipe replaced and replumbing the house. have put in new combi Baxi 105HE.
New mains is 25mm MDPE blue pipe. It will need to feed kitchen sink, dishwasher and washing machine downstairs, then upstairs for bathroom sink, shower, toilet then onto feed boiler. Bit concerned that boiler is at end of the line and could be robbed of pressure, so was thinking of reducing MDPE at stopcock to 22mm, taking a reducing tee off downstairs to feed kitchen sink/dishwasher, then running up wall, take treducing tee off to feed sink, shower and toilet, then reducing pipe to 15mm to feed boiler. does this sound over complicated?
Many thanks
Sponsored Links
Nothing wrong with what you suggest - running the mains in 22mm and spurring off with 15. Another possible quicker and cheaper solution would be to run a separate 15mm teed at the stopcock straight to the boiler - a roll of plastic pipe would get this installed quickly (but convert back to copper 1m from the boiler)
It's a Baxi and wont work half the time so don't worry about it.

Keep the pipe as large as possible all the way to the boiler, you will only be able to use one hot tap at a time anyway so it shouldn't be a problem.

It would be nice to know what the pressure is though.
It would be nice to know what the pressure is though.
Pressure (symbol: p or P) is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure ;) :LOL: :LOL: :LOL:
Sponsored Links
So it would be less in the Summer than the winter ;) or is it the other way round. :rolleyes:

Remind me to ask the sparky next time. :evil:

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local