"Owain" wrote in message
...
JustMe wrote:
To get the best performance from my new shower, you suggest I buy
pump+hot
water cylinder alongside my new shower head and mixer taps?

No; I suggest that you run the shower off the combi hot water and see
how that goes. That should be a fairly minor plumbing job as you only
have to run a hot pipe from the combi to the shower location. (I assume
that mains cold is already available for the existing electric shower,
washbasin etc. You may be able to take the hot from the existing
washbasin etc rather than going all the way back to the combi.)

The limiting factor of such an installation is (a) the flow available
from the mains, (b) the output of the combi. I think the Boiler Choice
FAQ [1] has details of how to measure your mains flow to determine
whether it is likely to be adequate.

If you then think you need more oomph you will have to look at some form
of stored and pumped hot water system. If you have inadequate flow
available from the mains, you will need stored and pumped anyway.

The hot water cylinder can be heated off the radiator circuit. Does that
mean use the same hot water as flows through the central heating - so
I'd be
showering in the water that might've passed through all the radiators?

No.

Or does that work differently?

Ordinary boilers have a closed circuit running through the boiler to the
radiators and a coil (heat exchanger) in the hot water cylinder. The
water in the closed circuit is heated in the boiler, and the heat
transfers to the water in the cylinder by means of the coil. The water
in the cylinder (that comes out of the taps) doesn't go through the
boiler.

Various means of valves, timers and thermostats control whether the hot
water in the closed circuit is circulated through the radiators (for
heating), through the cylinder coil (for hot water), or both, as required.

The combi boiler is exactly the same as far as the radiators are
concerned; it just has the additional function of instantaneous hot
water. You can add additional 'zones' to the radiator circuit to heat
different sets of radiators at different times, or add a hot water
cylinder to the circuit.

I've had a Google, and these look a lot like the big immersion heaters
I've
seen - presumably these can also be heated with dedicated electric
immersion, too? These seem somewhat bulky just for my personal shower
use
(single occupancy household) - or am I misunderstanding?

No, that's them.

The path would presumably be: Cold water supply - Hot Water Cylinder -
Pump - Shower head.

Yes.

I assume that the cylinder itself can be located anywhere near to the
shower - can that be above/below/same level, or does it need to be
somewhere
specific?

The cylinder can be anywhere, but the cold water header tank (which you
would also require) has to be higher than the shower. There are also
some restrictions on where you put the pump.

Owain


[1] Courtesy of Ed Sirett:
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he
http://www.makewrite.demon.co.uk/GasFittingStandards

Thanks a lot for your help.

I'll take your advise and run the shower direct from cold/hot water supplies
fed from mains/via combi to start with - even *I* can install that! I'll
just replace the bath taps with one of those all-in-one bath tap/shower hose
connection things and see how I get on.

Cheers.