Unvented Cylinder

[linton.jaw]

Hi, quick question. I am installing a Mira digital mixer valve (high pressure version). i have a single hot and cold pipe run from my mains cold water and unvented cylinder up to my loft room. Can i run all of my bathroom water from this run (toilet, bidet, his and hers sinks, bath and shower) The Mira book state "not to install the digital mixer valve onto a shared water supply." I can see i could have an issue with the flow rate not being good enough. My plumber has just left me the hot and cold supplies, would you recommend i ask him to come back and fit a seperate run for the mira shower?

Thanks

 

[Best]

No matter how you pipe it, the cold supply will be (most likely) a balanced cold which normally does all your bathrooms and the hot supply will be from one pipe leaving the unvented unit.
So they all are shared water supplies to an extent. There is always a certain amount of robbing other outlets if you open a tap and running the shower pipes back to unit will not stop that, although it is a benefit to tee off the larger pipes.
Depends on what diameter of pipes have been brought to bathroom and also hopefully flow rate & pressure are I assume good.
Actually, you could put the question to Mira themselves, although they mightn't be too sure about the answer I bet.

 

[linton.jaw]

I did think it would be a slight benefit to tee off the larger pipe (22mm) coming straight out the cylinder. However as you say, in effect it still will be a shared water supply! The pipes have been run to the bathroom in 15mm, The flow and pressure is really good. Pressure being 3 bar i think, but will double check that. I wish i had never read the "not to run shower on a shared supply pipe" line!!!!!!!!!

 

[Best]

15mm pipes will get robbed easier of volume of water and shower coming off 22mm would be better, but that would also mean the hot water will take longer to reach the bathroom compared to the smaller volume the 15mm pipe had which doesn't waste all that water! 15mm pipe at 3bar pressure with a decent flow rate is all you need for a bathroom. It is preferable to have the mains pressure hot pipe downsized to match each supply.
Just a pity the bathroom has to be shared! Can't you just put a lock on the door? :smile:

 

[linton.jaw]

Any more opinions on the mira digital shower requesting not to be installed on a shared water supply.