John Powell wrote:

I want a high flow system so I can have a decent shower

For an "ordinary" shower then this boiler would be more than adequate.
In fact anything that can do 10L/min or better will be more than you
need for a single shower usually.

- the builder's recommended a "Alpha CB50"

http://www.alpha-boilers.com/products/CB50.html

This provides a high flow rate - 18l/min @ 60 degrees C until the
internal 60l cylinder is exhausted, then a flow rate of 9-10 l/min @
45 degrees indefinitely

Is this an ideal system for a good shower? I'm concerned that my
showers are going to be short ones at a decent flow rate.

They make it quite tricky to find any technical specs on the web site -
but you can download the installation manual which has most of the info
you need. The boiler itself has a direct hot water heat input rating of
33kW - which is toward the larger end, but not the biggest you can buy.
Efficency at 80% is poor (and reduces the real DHW heating capacity to a
real world 26.4kW once its tank is cold). So most of the impressive DHW
performance comes from the 57L tank that is built in.

The main benefit of a storage system like this will tend to be better
performance when filling baths.

Would I be better going for a combi-boiler without an internal storage
cylinder, but a high flow rate anyway, perhaps the Baxi Combi 130HE?

I have no idea what Alpha are like, so will not give any recomendation.
If you want to shop around then I would have thought that it might be
worth looking at condencing combis with a heat input of 30kW or better.
There are a number to choose from.

Price looks OK at just over the grand:-

http://inspiredheating.co.uk/acatalo...D_COMBI_S.html


--
Cheers,

John.

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