"Andy Hall" wrote in message
...
On Wed, 17 Nov 2004 09:07:09 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .
On Wed, 17 Nov 2004 00:52:49 -0000, "IMM" wrote:



Typo on my part. Should have been
non-condensing. A weather compensator can
be on the rads circuit too. A weather compensator
can be an external controller rather than an
internal one (integrated with the boiler).
Danfoss Randall make one for around £160.

This is a poor way to do it because these controllers work by turning
the boiler on and off for variable periods.

It is not a poor way of doing it. Anti-cycle control is incorporated in
most
boilers and the compensator. I have had one switch a boiler for eons and
there is no excessive cycling at all. Coupled to a large mass of water,
like a heat bank, and cycling will be minimal to the point it is not an
issue.

Cycling a boiler at full output is a
very different issue than doing
so at 3kW in terms of efficiency.

It isn't. As I said cycling is not a issue as control and buffer measures
can be incorporated.

Since the discussion is based around
a modulating boiler, this type of
controller is irrelevant.

It isn't. To you it is as you are obsessed with your boiler. It is about
getting the most cost effective solution to a run a system to maximum
efficiency.

If the UFH heating is being run directly from a boiler dedicated to that
function then there are boilers around a lot cheaper with integral
weather
compensation as an extra, that will modulate down on the compensator
control.

Yes. The store also serves the DHW too.
So it replaces the header and
serves DHW, UFH and rads and prevents
boiler cycling.

The cycling issue is a corner case
and is irrelevant for the types of
boiler under consideration.

Once using a thermal store this
expensive boiler is then not an issue. A
cheaper simpler boiler can be used, that
is one of the selling points of
thermal stores/heat banks.

It is if you're DPS and trying
to flog heatbanks.

It is an issue for everyone as we all have boiler and people wanting most
efficient and simplest at the least cost. You know like all that free
market stuff you were on about, which in your tiny mind does not apply to
boilers or land.

However, if you are the purchaser, the equation may be quite
different,.

In this case with three functions: DHW, UFH and rads, all operating on
different temperatures, a heat bank/thermal store is by far the best
solution, maximising boiler efficiency.

You haven;t explained how all of
this can be done with the operating
parameters of the boiler type under
discussion.

What is under discussion is a system, not a single bloody boiler.

I think that you are simply bunching together all of the claimed
advantages and assuming that they all can happen concurrently. I
don't believe that that is possible.

See my recent post on this.