Shower - Will This Work?!!?!

Hello all,

Having ripped out my bathroom at the weekend and encountered a rather depressing problem. I thought that my cold water was gravity fed but i found it to be mains.
I'm trying to work out whether i can have a mixer shower or not.
Firstly i have purchased (before knowing about my CW) a manual shower mixing valve.
The hot water comes from a hotwater cylinder in the airing cupboard.
The current pressures for both the hot and cold water are ok but not great.
I really don't want to go buy a new electric shower.
so I'm proposing to set up this system...
Attaching a surrey flange to the top of the H/W cylinder and running a feed up through the loft and back down to the shower mixer. I would also pump this to create better HW pressure using a single impeller.
I would connect the mains cold water to the mixing valve.
I understand that the two pressures would be different but being a manual mixer, it shouldn't matter too much as i could adjust the temperature by adjusting the lever.
Would this system work? what are the pit falls?

I also wouldn't do this myself as i realise i have no plumbing skills

Thanks in advance

Trimmy

Tank feed the cold supply as well,Also use twin impellor pump!!

Terrywookfit's answer would make the most sense.
But if you only wanted to pump the hot and use the main, you would need to really put a pressure reducing valve on the main, to govern it down to the same as the pumped hot pressure, as the main could over ride the hot if its a strong pressure, and then the shower would only get warm.

thanks gents

what size tank would you recommend. 25,42 or 50 gallons, the shower would probably be used twice daily?

Thanks

50

Salamander recommend 50 gallon, but it really depends on the pressure and flow rate of your cold main supply. My own tank at home is 25 gallon, and it supplies two showers quite happily, with 3 bar 22mm fed stuart turner pump, never emptying cistern more than 1/3, and that is after about 10 minutes.