On Wed, 28 Dec 2005 15:55:17 -0000, "Doctor Drivel"
wrote:


"Andy Hall" aka Matt wrote in message
news
On Wed, 28 Dec 2005 14:52:55 -0000, "Doctor Drivel"
wrote:

But Matt....a CPSU has the DHW &
CH taken off the store of water and the
boiler "only" heats the store eliminating
boiler cycling. So the Heatflow
is not a CPSU.

If you think about it, since it's a
modulating boiler, it won't cycle
at any great rate when driving only
the heating circuit anyway.

Matt, the CH 'and' the DHW have to be taken off the store.

They don't *have* to be. This is just something that is implemented
on that type of appliance.



The ACV Heatmaster is a hybrid of
thermal store and unvented cylinder
(although to complicate matters the
unvented cylinder can be vented by
removing the pressure controls). The
CH is taken directly off the store of
water and DHW via an unvented
cylinder immersed in the store of
water heated by the store of water.
So, in effect a CPSU, but SEDUK don't think so.

Which demonstrates that the
definition is arbitrary, doesn't it.

No it isn't. Sedbuk got it wrong.

Oh of course, silly me. Which manufacturer's web site got it "right"

An immersed DHW coil or immersed DHW
cylinder are basically the same thing in this context. Both dipped inside a
thermal store.


--

..andy