On Sun, 12 Sep 2004 17:00:11 +0100, Pete C
wrote:

On Sat, 11 Sep 2004 22:14:01 +0100, Andy Hall
wrote:

Having an analogue control is a much better way.

Bit unnecessary for a non modulating boiler I would have thought.

Except that the Keston Celsius 25 is a modulating boiler........

Ooops, I'm not a boiler spotter )) Does the temperature control
affect CH as well as DHW? I'd have thought it only affects DHW, and
the rest of the time the boiler operates in condensing mode where
possible.

It isn't a combi either.



For DHW it could be useful to have a lower output temp for bath
filling, this could be done with a preset and changeover relay.

For more control something could be done with the flow and return
thermistors.

I have this functionality on my (MAN Micromat) boiler.

http://www.man-heiztechnik.de/index_e.php

It has an outside temperature sensor as well as an indoor one, and
programmable curves for CH operating temperature vs. environmental
temperatures. It will thus modulate the CH temperature down to
around 40 degrees and 3kW if there is not a great heat demand.

For DHW, there is a temperature sensor in a pocket in the cylinder
which starts a hot water reheat cycle when a rapid drop in temperature
is detected. In this mode, the boiler is run up to full output to
reheat the cylinder rapidly.




cheers,
Pete.

..andy

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