"Dave" wrote in message
...
"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Dave wrote:
...snipped
- I need 3 heating zones, what's the advantage of using a pump for
each zone rather than one pump and 3 zone valves?
With 3 pumps you can match each pump to the requirements of a single
circuit - but the control logic is a lot more complicated, particulrly
if
the boiler needs pump over-run (which pump over-runs?)

A single pump has to be able to run all 3 circuits - but on occasions
will
only need to run one. Maybe one of these fancy variable output devices
(Alpha or somesuch?) would be worth considering. The control logic is
much
simpler - using an S-Plan+ setup.

Good point. So the pumps would be standard 3-speed types, each set to the
optimum speed for that zone and controlled directly by the timers/stats
(possibly with relays).

Yep.

...snipped
- Because the cylinder will be in the garage I want a recirculating
pump on the DHW but how can this work when the water is just being
recirculated around pipework and not through a heat source?
I don't understand this bit! Surely the idea of a heat bank is that DHW
is
at mains pressure - and gets heated by the heat bank on its way to the
taps?
In this case, how can it be circulated round the taps when there is no
outflow?

I don't understand it either but it's a "standard option (!)", Christian
has
made a good suggestion so I'll investigate further.

... snipped
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Cheers,
Set Square
______

Thanks.
Dave S