Shower pressure help

[Gassaferob3]

Hi all.

I'm about to remodel the bathroom. We're getting rid of the bath and going to have a large shower enclosure.

I would really love to have a large ceiling rose and a rail unit too. I would like to have them working at the same time.

I'll be running this off a combi boiler (37kw)

I have good water pressure coming in. My question is will this be enough or should I fit a pump?

If so can one pump feed both rose and rail, or do I need separate pump for each?

Advice is greatly appreciated.

Thanks

 

[blackfriars]

hi , not with the 2 heads
use this calculation
Handy rule: multiply the hot water flow rate in litres/minute by the
temperature rise in °C. Divide by 100 and multiply by 7 to get the
boiler DHW output in kW.
Example: 12 litre/min at 40°C rise: 12 x 40 = 480.
480/100 = 4.8.
4.8 x 7 = 33.6kW boiler DHW output.
your large center shower head would likely use 15lts per min on it's own

 

[Gassaferob3]

Thanks Blackfriars, handy calculation to remember.

So what your saying is I'll need two pumps?

Or can I use the boiler to run the rail unit and a pump to run the rose?

 

[picasso]

You cant put a pump on a combi, if you have good pressure coming into your house (more than 14 litres per minute) ? then that is all the combi can do.

 

[blackfriars]

hi , no , what i am saying is your combi won't have capacity to heat the water for both heads at the same time to any decent degree
you can't use a pump as a combi has a max capacity of flow x heat lts per kw p/min, you are not allowed pump mains water for a combi
depending on water pressure /flowrate

you can run a mixer shower direct from a combi

other option is storage tank / hot water cylinder connected to the combi on a "s" plan and a shower booster pump with say 18/20lts per min and 3 bar pressure

 

[Gassaferob3]

hi , no , what i am saying is your combi won't have capacity to heat the water for both heads at the same time to any decent degree
you can't use a pump as a combi has a max capacity of flow x heat lts per kw p/min, you are not allowed pump mains water for a combi
depending on water pressure /flowrate

you can run a mixer shower direct from a combi

other option is storage tank / hot water cylinder connected to the combi on a "s" plan and a shower booster pump with say 18/20lts per min and 3 bar pressure

Cheers.
My boiler is fairly new so not wanting to change it just yet. Mixer shower seems only realistic option then. So mixers taps with no diverter.

Oh well, should of thought ahead!!