In an earlier contribution to this discussion,
Andy Hall wrote:

On 2007-12-25 23:35:52 +0000, "Roger Mills"
said:

But the S-Plan as defined in
http://content.honeywell.com/uk/homes/systems.htm just has a timer
and stat controlling each valve with equal priority. Although you
*could* muck about with that to provide HW priority, Honeywell
haven't actually done that - in any of the examples I have seen, at
any rate.

They don't exclude anything in their specifications.


But by the same logic you could argue that a car is the same as a motorbike
because it has an engine which causes the driving wheel(s) to rotate. The
fact that you've added extra wheels and seats and a steering wheel and roof
is insignificant.



Honeywell says:

The main operating requirements of Sundial Plans a

1.The controls should provide full independent temperature control
of both living space and stored domestic ho****er.

2. If there is no demand for either living space or domestic hot
water heating, the central heating boiler and pump must both be
switched off.


That applies to *all* plans - even the C-Plan

Exactly. The functionality is not limited by the specs. It is
the valves that limit the functionality.


I don't see what you're getting at. The functionality of an S-Plan system is
achieved by means of a combination of the valves, timers and stats. You
could, if you wished, achieve a different fuctionality with the self-same
valves, simply by changing the external control logic. It's just that it
would no longer be an S-Plan system.
--
Cheers,
Roger
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