Roger Mills wrote:
In an earlier contribution to this discussion,
John Rumm wrote:

ARWadsworth wrote:

The web archive link works fine here. All those nice drawings are
back. The ones that I and Roger wanted.
You don't want those.... Dave has drawn a much nicer set:

http://www.diyfaq.org.uk/docs/SundialPlansRev1.pdf

(just sticking gif versions up on the wiki now, so we can have them
inline in the articles)


Yes, they're pretty good!

I would, however, query the comment which goes with C-Plan about being
completely obsolete and unsuitable for either new systems or refurbishments.
I agree about new systems, but there are still a lot of gravity HW systems
out there which would benefit from being converted to C-Plan - which
requires very little plumbing and delivers considerable efficiency
improvements relative to the status quo. The only downside compared with a
fully pumped system is that when just HW is being heated, the boiler is on
for longer than it otherwise would be - albeit cycling on its stat rather
than firing continuously.

I did pause on reading Dave's comment on the schematic, and wonder it it
was a little "absolute". While it is true you would not start from there
today, I also take your point that it could be an improvement on a
unvalved gravity system... (IIRC, prior to modern zone valves and
cylinder stats etc, there used to be a type of wax capsule valve you
could fit to a cylinder to quench the gravity flow when it was to
temperature - can't remember the name of it alas)

Does anyone have any evidence that this does not meet Part-L, and would thus
presumably be illegal as an upgrade from a 'conventional' gravity HW/pumped
CH system?

Depends on your interpretation I guess. Part L requires fully pumped
IIRC, but then again most BCOs will be pragmatic and recognise a non
ideal situation that is actually an improvement on what was there.

(having said that I expect the target audience for this sort of info is
not going to be the rip and replace to building regs demographic!)

I'm still not sure about the way in which Y-Plan's mid-position valve is
depicted. As everyone knows, it has two microswitches and other components
in addition to the motor. I still tend to the view that we should either
show *all* internal connections (as for other types of valve) or *none* (as
per Honeywell's original Y-Plan diagram).

I have no objection to showing all internals - but I am not sure it adds
much given context of what the wiring diagram is attempting to show. One
could add a note to say that this is a "simplification" that is really
there to show the orange wires is switched to provide a call for heat -
even if the actual mechanism is not depicted accurately.

Thinking about it, perhaps we could show it empty, but with a note to
see another diagram for details, and then maybe Dave would be kind
enough to redraw the diagram we have he

http://www.diyfaq.org.uk/plumbing/co...itionvalve.htm

(oh, just noticed Geoff's email link is broken in that...)




--
Cheers,

John.

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