Pipe query

[22gb]

Long time reader, 1st time poster.
So I'm planning to change some pipes before I re-do bathroom and decorate the bedroom above it. I plan on running 22mm and branching off 15mm to kitchen and other taps. What I am unsure about is weather to have a 22mm branch to the bath and shower before any of the 15mm branches start further down the line so shower and bath has its own line for hot and coldor weather to just have the shower and bath at the end of the run as it is now (shower doesn't currently exist).
I'm presuming it's better to have a 22mm feed for shower.
Also while I'm at it I was going to change the cold for balanced cold and have every thing thats cold running off that, so that my supply is straight to the combination valve instead of various branches before it.
Main line in is 25mm and new, It may also be worth noting that combination valve and unvented cylinder is in the loft and bathroom is on ground floor so pip runs may be longer than if bathroom was upstairs.
Any comments appreciated, thanks!

 

[22gb]

I should have said, the outlet from the combination valve for my balanced cold is currently a blanked off stub which is why I'm thinking of using it for everything while I'm doing other pipework, instead of just for a shower.
If I use balanced cold for shower only then I would end up with tee off to kitchen and bathroom cold supply before the feed to the cylinder, which I though might not be ideal, but....
Am I over complicating it?

 

[king of pipes]

The balanced cold is normally used for shower connections as shower mixers work better with balanced hot and cold supplies , other colds ie in the kichen , bath ect can come direct from the rising main you cannot fit a unvented cylinder you will need a qualified plumber with certification to do that and building control will need to be informed.

 

[22gb]

Thank you, the system is already in place for the last couple of years, The balanced cold was left blanked as at the time there was no shower, which is the work that's being done now hence the questions.
Is it ok the branch off kitchen etc before the cylinder? It won't affect flow if shower is running and kitchen tap is turned on?

 

[king of pipes]

Yes thats ok you should be fine as you have a new 25 mm mdpe main providing you have a good pressure suppling it regards k

 

[22gb]

Ok. Thanks for your help, I will plan to do it that way then.

 

[22gb]

OK, I have one last question before I start.
Would I be better to run separate pipes for the shower from the cylinder, considering I have floors up it would be possible at this time. At the moment the bath is at the end of the line, so if I turn another hot tap on I notice a drop in flow at the bath. If the bath/shower was tee'd in at the start of the line and before the others tee in, would it imporove shower performance or would it be the roughly the same as current?

At the moment flow is: I work it out at 14 liters/min at the bath (this is the highest output of all my taps) and 12liters a min at bath with kitchen hot open aswell, obviously lower again if another tap is open too. This is similar for hot and cold. I will be changing the 15mm supply after stopcock to 22mm all the way thru.

 

[22gb]

OK, I have one last question before I start.
Would I be better to run separate pipes for the shower from the cylinder, considering I have floors up it would be possible at this time. At the moment the bath is at the end of the line, so if I turn another hot tap on I notice a drop in flow at the bath. If the bath/shower was tee'd in at the start of the line and before the others tee in, would it imporove shower performance or would it be the roughly the same as current?

At the moment flow is: I work it out at 14 liters/min at the bath (this is the highest output of all my taps) and 12liters a min at bath with kitchen hot open aswell, obviously lower again if another tap is open too. This is similar for hot and cold. I will be changing the 15mm supply after stopcock to 22mm all the way thru.

 

[Chalked]

It depends on your inconming msins pressure and flow. If you only get 15litres a min, there's my point running extra pipework. Just do as much as possible with 22mm

 

[22gb]

So would it be worth checking mains pressure 1st to see where I am? Or would you think to just replace the 15mm feed section with 22mm and tee in shower with the bath at the end of the line?

 

[ShaunCorbs]

So would it be worth checking mains pressure 1st to see where I am? Or would you think to just replace the 15mm feed section with 22mm and tee in shower with the bath at the end of the line?

it would be yes no point running the extra pressure if you only have less than your reducing valve is reducing to

 

[22gb]

Yes, that makes sense. Even if it turns out to be low pressure, Would it not be worth connecting off the balanced anyway incase of future pressure changes?

 

[ceemee]

<a href="https://web.************" rel="nofollow">Thanks for sharing your ideas.</a>

 

[22gb]

What's that? Link doesn't work mate.
Cheers

 

[22gb]

What's that? Link doesn't work mate.
Cheers

 

[22gb]

Pressure is around 2.3bar (not directly at stopcock but a few meters from it, but still at ground floor level)
Pressure drops to around 1.5 bar with a tap open. Interestingly it drops more it's the bath tap that's opened, down to 1bar.