Easy shower installation!

Hello plumbers

I have a couple of things I would like to ask if you. If you have the time to help me I would be very thankful to you all.

Firstly, I am intending on installing a mixer shower over my bath.

I am a keen diy plumber but would like so expert advice or tips before I begin.

What is the difference between a manual mixer or a thermostatic shower mixer? Does it have a thermostat dial to adjust water level?

Also, when running a dedicated cold feed pipe to the mixer from my cold water tank in the loft space, is it ok for the pipe to run at a slight fall until it comes through the ceiling, and then drop vertically, and then run off at about 45 degrees or so to the manual shower mixer? Will this cause airlocks at all? Anything I should do to make the installation better?

The hot feed will come from a flange at the top of the hot water cylinder that is situated behind the bath in my airing cupboard.

Thanks again for listening. I hope you can help.

a thermostatic mixer has a thermostatic cartridge inside so if someone else runs a cold tap etc the temp in the shower don't go scalding hot it balances it out to a even temp.

you may find in your situation you'll need a pump running off gravity flows the shower will be poor.

i have about 1 metre or so of head, so shouldn't need a pump. have seen a few friends' showers similar and they run fine without one.

1 metre to shower head is only 0.1 bar.
they can run ok but not powerful

It is possible to get a reasonable flow rate with low water pressure, but you will need to take care to select a shower mixer and head designed specifically for gravity water pressures.

It will never pin you against the wall with a jet of water, but it can certainly be sufficient to get you very wet.

Raising the cold water storage tank as high as possible may improve the pressure a little, maybe you could achieve 0.2 bar pressure. Even then mixers designed for mains pressure would only deliver a pathetic dribble at gravity system pressures. They are usually designed for a minimum pressure of 1 bar or more.

As the other posters say you will not get a good shower from gravity feed especially the way shower valves are manufactured nowadays, I would either pump it or use a power shower like these little cheapies http://www.tapstore.com/acatalog/New_Team_power_showers.html
Bristan do make a shower that does work off of 0.1 barhttp://www.tapstore.com/acatalog/copy_of_java_shower_with_adjustable_riser.html but I would not say you will get a great shower from even one that say's it will work at that pressure.