Bathroom and ensuite pipe sizing

[Gaz the Sparky]

Hi Im currently refitting my bathroom and then my ensuite.

I've just had a new unvented cylinder fitted. There is a 22mm cold feed to the tank and a 22mm hot feed from the tank. These both disappear under the floor where a 15mm pipe branches off the cold and hot and feeds to the downstairs toilet sink and to the old bath.

then a 22mm hot and cold go off to the ensuite and 2 sink connections (1 bathroom sink 1 ensuite sink), 1 mixer shower and 2 toilet connections (1 ensuite toilet and 1 bathroom toilet) come off this.

I am fitting a bath tap as well as a mixer shower in the bathroom so would I be better to run a 22mm hot and cold to the bath and branch off 3 15mm pipes

1 to the bath tap
1 to the bath mixer shower
1 to the downstairs toilet

Then in the ensuite should I keep the 22mm hot and cold feeds as they are?

I am planning to have a walk in shower with rain head. Should I run dedicated 15mm supply pipes back to the cylinder or keep the existing shower feeds off of the 22mm feed along with the toilets and sinks will this be ok ?

When I had the cylinder fitted they haven't installed the balanced cold feed and I have read that mixer showers should be fed from this Balanced feed.

If this is the case should I leave the all the other sinks and toilets as they are and just install a balanced cold supply to the showers and bath mixer tap

or should I just install all the cold feeds to the bathroom and ensuite off of the balanced feed
(toilets, sinks and outside tap branched off the downstairs toilet sink)

just want to make sure i have the correct size pipework in before the new floors get screwed down

cheers

 

[Madrab]

To minimise any drop in performance to any single outlet on a shared supply, keep the pipework at it's largest until branching to the outlets. Especially when mains fed, where the pressure and flow are suitable.

The balanced supply from the unvented control group is there for a reason. Use it where/when you are mixing hot and cold supplies within single flow (mix in the body) outlets to ensure maximum performance.

 

[Gaz the Sparky]

That’s great thanks for the info.

I’m going to change the 15mm to the bath and run 22 and branch off 15mm to the shower and bath taps and then pick up the 15mm going to the downstairs loo sink.

So I connect this new 22mm cold feed to the balanced outlet.

Would it do any harm the toilets being fed off this balanced supply or should I run a mains cold feed aswell.

The boiler is in the garage and the filling loop branches off the current bathroom cold feed is this ok to be off the balanced feed or does this need to be mains ?

The same with the outside tap, I was planning on teeing into the downstairs toilet feed but this will be reconnected to the new balanced feed.

I have to do all the sinks as all the sinks and baths and showers have mixed outlets.

 

[Madrab]

Yes, that'll be fine as far as the branch approach.

Try to dedicate the balanced supply to the mixer outlets to minimise any impact when using other individual hot/cold outlets at the same time (toilet etc)

Run any individual outlets - boiler/toilets/etc - from the mains supply if possible.

Of course any drop off in performance will always be reliant on the mains being suitably sized and fed.