In article ,
The Natural Philosopher writes:

Remember the boiler itself will lose a lot of heat to the room its in.

Depends on the boiler.

Potterton Profile probably gives off up to 200W from its case
(that was the typical value for boilers of that age).

When I installed a condensing Keston, I tried to find the figure in
the data sheets (to calculate how much extra the radiator in that
room needed to add). I couldn't find it, so just assumed 200W.
That turned out to be a mistake. In the Keston, any heat which
leaks out through the heat exchanger is recycled back into the burner
air inlet, so the case doesn't get hot, and it doesn't heat the room.
I doubt any more than 20W leaks out, and that's only after the burner
has been on for a long time.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 21/10/2011 16:23, Dave wrote:


What's the best way (and by that I think I mean the cheapest way) of
heating just one room? We have a box room that I'm going to set up as an
office as I'm now going to be working from home. I assume that the way
NOT to do it is have the full house central heating on and turn down (or
off?) the TRVs in all the other rooms?

It's a 1960s semi-detached dormer (chalet) bungalow with one external
wall being "normal" brick/cavity/brick, the other external wall has the
window and has (I think) inner plasterboard/wood frame/outer tile
construction and the other two walls are standard stud walls.

In case anyone was going to suggest one of those stand-alone gas
heaters, I assume it would have to go on the brick wall but due to the
room layout, that wall is the best choice for the desk and shelving so
I'm afraid that's a non-starter.

Good insulation and a BIG PC ;-)

In article ,
(Andrew Gabriel) writes:
In article ,
NT writes:
Is thermal cycling a major failure mode in boilers? I didnt think it
was.

Sorry, misread that as a major source of inefficiency...

It's down to the boiler design.

I have a 20 year old Potterton Profile which is designed to cycle
as it can't modulate, and does so very efficiently with no waste
in the cycle.

OTOH, I have a 10 year old condensing Keston which is designed to
moduate down to 7kW, but cycles below that. The cycling in this
case is not at all efficient or well designed, and it would be
bad practice to design a system which relied on this boiler
cycling to generate 7kW.


--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

i'm looking for an under desk heating mat
like this canadian one,
will start a new thread...

http://www.tesco-shopping.com/Cozy_heaters.htm

On Oct 21, 3:23*pm, Dave wrote:
What's the best way (and by that I think I mean the cheapest way) of
heating just one room? We have a box room that I'm going to set up as an
office as I'm now going to be working from home. I assume that the way
NOT to do it is have the full house central heating on and turn down (or
off?) the TRVs in all the other rooms?

It's a 1960s semi-detached dormer (chalet) bungalow with one external
wall being "normal" brick/cavity/brick, the other external wall has the
window and has (I think) inner plasterboard/wood frame/outer tile
construction and the other two walls are standard stud walls.

In case anyone was going to suggest one of those stand-alone gas
heaters, I assume it would have to go on the brick wall but due to the
room layout, that wall is the best choice for the desk and shelving so
I'm afraid that's a non-starter.

TIA

Try one of those small and cheap electric heaters... not the fan
controlled ones. The coil or radiator like heaters should solve your
problem in a few minutes every 3 or 4 hours. You can even temperature
control them these days.
-John.

On 24/10/2011 14:09, Dave Plowman (News) wrote:
In ,
The Natural wrote:
Still has to arrange a LOT of extra wiring somewhere and maybe Motorised
valves.

Indeed. If you split the rest of the house up into one zone at the boiler,
you'd need to run new pipework to the room in question. Only alternative
to that I can think of would be some form of radio linked TRVs on every
rad, centrally controlled. But even something like this exists, it
wouldn't be cheap to either buy or install.

If there is an option to get the wiring around (12V will do), a resistor
added to the head of each TRV can easily close off the unwanted
radiators. Then a wireless (mobile) stat would work fine.

Not what I'd do, but it is a cheapish option.

Ours actually does have wired timer/stats and motorised valves per room.
All run through relays and 12V so that the stats could be wired in alarm
cable up the edges of doorframes, so as to avoid redecorating the whole
house. The boiler does sometimes short cycle, but I can live with that -
it's all been running that way for over eight years now and the boiler
boiler is 10 years old.

SteveW

On 24/10/2011 17:55, Dave Plowman (News) wrote:
In article
,
wrote:
Be interested to know just how you could zone off one room in a house
that simply. Without loads of extra pipework.

We dont know the op's plumbing layout. It may be as simple as adding
valves, or it may need added pipework.

Give me an example of how.


Do you understand how zoning is
achieved?

One sole existing zone can be subdivided after the event.

You could cut off one room quite easily. But cutting off the rest of the
house while leaving on that room is the tricky thing. Think about it.

In a previous post, I've suggested that one option for doing this is a
low voltage supply, heating resistors added to the heads of the TRVs in
the other rooms.

SteveW