In a post a few days ago, off-topic I mentioned (in Jest!) using an old 23KW
gas multipoint water heater to heat a thermal store for a new CH system. It
ended with me thinking I'd ditch the multipoint to make way for the
cylinder. Err, well... see below.

First, a question relating to thermal stores. To promote a cool return
temperature I'm contemplating that I may (or may not!) need to run my
1300mm/210L store at a lower temperature - say 70 degr rather than 80. To
compensate, I was going to get Newarkcyl to add one or two alternative
tappings a bit higher up the cyl for the space heating take-off. But I'm
working blind, I don't have the foggiest what the existing return
temperatures will be, or where to ask for the extra holes to be. Any ideas?

And one other thing, what is the difference between a 'vented' CH boiler and
a multipoint - both just heat water don't they (:-).

I just couln't let go of the idea of a free (installed) CH boiler. There
*will* be a thermal store - the only issue now is what & where the boiler
will be. If the council don't object on Part L (It's an existing boiler)
then I'll hook up the multipoint. I now plan to put the store on the ground
floor, under the stairs in the middle of the house. The primary pipes will
run to the multipoint boiler along a path that will run close to the (ground
floor) siting of any new Condenser boiler - if and when that happens. F&E
tanks in the loft. Pumps near to the store (maybe).

At the moment I'm now planning on doing it as Dr Evil suggested - integrated
with common primary water to boiler, store and radiators. There might be
risk of the Fernoxified, sludgy brown water affecting the multipoit's
rubbery flow sensors? but I'll take a chance. And as the store is now
downstairs, in the event of a catastrophic leak upstairs at least the
cylinder contents wouldn't add to the flood.

One thing that occurred to me is that the water in the multipoint would
generally be hotter than if heating from the cold mains. And as the pressure
via the F&E will be relatively low this might risk 'kettling"? For this
reason I'd like the return temperature to the boiler to be cool. On the
other hand, if fitting a condensing boiler (now or in future) then again I'd
like the ruturn temperature to be cool to promote condensing. So, I've gone
for a somewhat oversized 1300mm, 210L thermal store, Newarkcyl, to aid
'stratification'. Two stats as well - external as these give positioning
flexibility.

And if the above is completely mad let me know!.

Thanks DIYSOS.