In an earlier contribution to this discussion,
Mark Trueman wrote:

Hi,

Current system - gravity HW, pumped CH. HW must be on for CH to be
on. Runs off a Drayton Lifestyle LP241 timer. No stats or TRVs on
rads, when its on, its on full blast.

Anyway, im thinking about adding a room stat to try to control the
temp a bit better. Didnt mind it getting to 25 degrees previously,
but now my new marine fish tank is not liking the increase in room
temp.

Anyway, i digress. Looking at installing the Drayton Digistat 2.
Looks easy enough to wire up from looking at the LP241 instructions.

What i want to know is; is there a better/cheaper alternative room
stat (24 hour version is fine, 7 day version is even better). And if
there is, is the wiring likely to be the same?

Regards

Mark

With your existing setup, all you can really do with a room stat is switch
the pump on and off - so, whenever heating is selected by the main
programmer, the boiler will cycle on its own stat - and the DHW will
continue to get hot(ter) by gravity circulation.

A room stat will help to stop the house from getting too hot - but it won't
prevent the boiler from wasting engergy by cycling needlessly, nor will it
prevent the DHW from overheating.

If you're wishing to improve the overall control of your system, you should
seriously consider installing a zone valve in the gravity HW circuit and a
cylinder stat on the hot water cylinder, in order to convert it into a
C-Plan system. [See http://content.honeywell.com/uk/homes/systems.htm ]

This will provide a boiler interlock to ensure that the boiler only runs
when needed - and will provide much better control over DHW temperature.
--
Cheers,
Set Square
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