On Tue, 4 Jul 2006 01:01:43 +0100, Anode wrote
(in article ):


"Dave Plowman (News)" wrote in message
...
In article ,
Anode wrote:
At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too
hot, or off.

Surely in most cases it's the temperature of the room that matters?

Thus the radiators cycle between being much hotter than is needed for
just compensating for heat losses from the rooms, producing
unpleasantly hot air around the radiators, and then cycling to a period
of being colder than they need to be.

Are you forced to be that close to the rads? I've got one so close to this
computer I can touch it from the chair, but I'm not aware of heat actually
radiating from it - and certainly not hot air which rises.

That's not to say a modulating boiler isn't a good idea - I shall get one
when it comes time to change mine. But this will be for efficiency reasons
rather than comfort.

--

Dave Plowman


It could be just a personal thing, but radiators above a certain temperature
I find unpleasant and best avoided; it seems to be something to do with
breathing in the hot air from around them so I was trying to avoid this in
future alterations. I understand that comfort level is affected by many
factors, including relative humidity and radiant heat emission from walls
and objects in the room, so personal comfort can no doubt be a complex
concept.

Anode.



If that's your only issue rather than having a more or less constant
temperature, you could resolve it quite easily.

For conventional boilers, radiators are run at 82 degrees flow and 70 return.
Radiators are sized for the room heat loss requirement to work with this.

If you install a condensing boiler, it *can* work at these temperatures -
they do to avoid mandating radiator changes. However, it will operate more
effiiciently at lower temperatures, so it is more typical to design for 70
flow and 50 return. Heat output is then about 30% less so the radiators
have to be larger. There is no reason why you couldn't extend this
principle further, use even larger radiators and lower temperatures.