Fitting a thermo mixer

Hi, I want to put a shower in our middle floor bathroom.
I have a condensing boiler upstairs and also a en-suite with a shower, I have good pressure in the middle bathroom where I want to fix shower and it will be over the bath. Can I put a t-piece on the bath taps supply hot and cold and then run them up the wall to the mixer? (I can\\\'t put a tap shower on as the taps are on the side of the bath now where near the walls).

You don't say what sort of hot and cold water system you have.

not sure thats why, umm condensing boiler I don't have a cold header tank in the loft, all I have is the boiler in the airing cupboard, with the expansion chamber thing, sorry

So it's a combi boiler (make and model?) - then you have mains pressure hot and cold.

The answer to your original question is that you can just branch off existing pipes, which should be 15mm. But be aware that a combi boiler will only deliver so much hot water (typically 10 litres/minute depending on output) and it will not be able to supply much more than one outlet at a time. So when two or more outlets (e.g. showers) are open, the lowest outlet will tend to get the hot water flow, starving the higher one.

Thanks Chris although I'm not sure that it is a combi boiler as it has a 85 litre tank within it, with that I take it that its ok to do it as well
Here is a link to my boiler
http://www.potterton.co.uk/products/gas/highEfficiency/powermaxHE.html

It would help if you gave such information at start of thread .

OK you've got plenty of hot water flow available, subject to your cold mains supply being up to it (is it?). Answer to your main question remains as above.

So just how feasible is it to feed a shower from a combi boiler? I note with interest the comments regarding flow rates from a combi boiler but do you need to buy a mixer valve/shower specifically for a combi type hot water system or will any one do provided you carefully study the flow characteristics of both the mixer and boiler?

Thing is, I live in a bungalow which has a combi boiler in the loft (adjacent to a loft conversion) and an electric shower which isn't that powerful, given that I prefer a shower that will pin me to the opposite wall with sheer force of the water jet

My other options are possibly installing a higher wattage shower but that will mean uprating the 6mm2 cable (and will the end result be worth it?) or installing a hot water tank heated from a timed emersion heater and a seperate pump for the power. The mains pressure appears to be good.

I've also heard of gas showers.... never seen one but I'd assume it has it's own heating system.

All comments and advice gratefully received.

Cheers,
Jon.