Domestic CH - to zone or not to zone...

390 views
Skip to first unread message

Mike Barnard

unread,
Jun 27, 2007, 9:14:24 AM6/27/07
to
Hi all.

Any CH design guru's aid me in my small dilemma please?

I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
CH at all untill a couple of years ago when I put a new combi boiler
in [1]. I also put a couple of rads in. It was not a complete system,
DHW was what I needed mostly. Now the time has finally come to finish
the job.

The dilemma is whether to zone off the rear two rooms upstairs. The
bathroom and bedroom 2 are north facing and in winter they can be much
colder than the rest of the house. The thremostat and timing controls
are in the open plan lounge; see description below. If the lounge is
nice and toasty, then the thermostat will not be telling the boiler to
fire up. Therefore the water in the pipes will not be heated and
under circulation. No matter how far the TRV's in these rooms open
they will recieve no heat.

Thoughts:

If I put a zone in to supply heat for these rooms its a lot more
pipework and electrics to try and hide.

If I'm doing these two rooms why not all of them.

If I do all of them am I going to lose heat when the upstairs is off
and downstairs is leaching up?

What else?

Layout is...

Front is facing south, rear north. 1 mile from the sea.

Front door opens directly to the living room.

Ground floor split into just two rooms:
- a living room to the front
- a dining room / kitchen to the rear

Open staircase from the living room to a landing.

Off the landing at the back is the bathroom and bedroom 2, (my 5yo
sons.)

Off the landing to the front is bedroom 1 (ours) and bedroom 3 (used
as a study.)

Radiator with no TRV in the lounge as the controls are here by the
stairs.
Radiators with TRV's in all other rooms.
Heated towel rail in bathroom.

Thanks for any eyeopeners.

Mike.

[1] Worcester Bosch Greenstar R35HE Plus. What a mouthful. As a
part of putting in a new kitchen, losing an airing cupboard and a wall
and associated HW tank and plumbing.

EricP

unread,
Jun 27, 2007, 9:38:20 AM6/27/07
to
On Wed, 27 Jun 2007 14:14:24 +0100, Mike Barnard
<m.barnard...@thunderin.co.uk> wrote:

>Hi all.
>
>Any CH design guru's aid me in my small dilemma please?
>
>I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
>CH at all untill a couple of years ago when I put a new combi boiler
>in [1]. I also put a couple of rads in. It was not a complete system,
>DHW was what I needed mostly. Now the time has finally come to finish
>the job.
>
>The dilemma is whether to zone off the rear two rooms upstairs. The
>bathroom and bedroom 2 are north facing and in winter they can be much
>colder than the rest of the house. The thremostat and timing controls
>are in the open plan lounge; see description below. If the lounge is
>nice and toasty, then the thermostat will not be telling the boiler to
>fire up. Therefore the water in the pipes will not be heated and
>under circulation. No matter how far the TRV's in these rooms open
>they will recieve no heat.
>
>Thoughts:
>

Well I didn't "zone" and bitterly regret it, so go figure from that.

Do any work you think will improve the system. You will think of
plenty when it's too late.

Roger Mills

unread,
Jun 27, 2007, 10:01:41 AM6/27/07
to
In an earlier contribution to this discussion,
Mike Barnard <m.barnard...@thunderin.co.uk> wrote:

> Hi all.
>
> Any CH design guru's aid me in my small dilemma please?
>
> I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
> CH at all untill a couple of years ago when I put a new combi boiler
> in [1]. I also put a couple of rads in. It was not a complete system,
> DHW was what I needed mostly. Now the time has finally come to finish
> the job.
>
> The dilemma is whether to zone off the rear two rooms upstairs. The
> bathroom and bedroom 2 are north facing and in winter they can be much
> colder than the rest of the house. The thremostat and timing controls
> are in the open plan lounge; see description below. If the lounge is
> nice and toasty, then the thermostat will not be telling the boiler to
> fire up. Therefore the water in the pipes will not be heated and
> under circulation. No matter how far the TRV's in these rooms open
> they will recieve no heat.
>

With a properly designed and balanced system (with radiators of an
appropriate size in each room/space to balance the heat loss - and with the
lockshields adjusted to give the same temperature differential across each
radiator) there's no reason why one room should be significantly hotter or
colder than any other.

Zoning comes into its own if you want to heat different parts of the house
at different times. Otherwise there's not all that much point. If it's easy
to do, do it anyway - because it gives slightly better control over
different areas (with a room stat for each area) - but if it's a pain,
plumbing-wise, don't bother.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!


JoeJoe

unread,
Jun 27, 2007, 10:01:11 AM6/27/07
to

"EricP" <er...@blueyonder.co.uk> wrote in message
news:0up4831vjjmktqare...@4ax.com...

Same here. Feeling rather silly heating the whole house when upstairs is
empty. Also, we find it quite difficult to avoid overheating the kids
bedrooms in the evening when they are already in bed and we are still
downstairs (bedrooms were added much later and are much better insulated).

NoSpam

unread,
Jun 27, 2007, 11:04:24 AM6/27/07
to
Mike Barnard wrote:
> Hi all.
>
> Any CH design guru's aid me in my small dilemma please?
>
> I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
> CH at all untill a couple of years ago when I put a new combi boiler
> in [1]. I also put a couple of rads in. It was not a complete system,
> DHW was what I needed mostly. Now the time has finally come to finish
> the job.
>
> The dilemma is whether to zone off the rear two rooms upstairs. The
> bathroom and bedroom 2 are north facing and in winter they can be much
> colder than the rest of the house. The thremostat and timing controls
> are in the open plan lounge; see description below. If the lounge is
> nice and toasty, then the thermostat will not be telling the boiler to
> fire up. Therefore the water in the pipes will not be heated and
> under circulation. No matter how far the TRV's in these rooms open
> they will recieve no heat.
>
... snipped

I re-did our heating a while ago and split it into 3 zones: downstairs,
upstairs (less bathrooms), bathrooms+airing_cupboard+workshop. There
were a number of people saying it was a waste of effort because of the
open staircase. In practise it's been great. If I'm working at home
during the day I have the downstairs heating on and the upstairs stays
cold. The only regret is that I didn't add a fourth zone for just the
office.

Dave

The Natural Philosopher

unread,
Jun 27, 2007, 12:39:58 PM6/27/07
to

Mike. Its a contstant dilemma..

Ny feelings are as follows. First of all Radio stats are not THAT
expensive and save a lot of wiring, and TRV's are even cheaper.

What might be worth doing is adding - say - trv's to everything, and
plumb in a bypass loop, and then put a radio stat in the coldest room so
that at the least, the heating would stay on till that one was warm..you
could simply parallel the output of the existing stat and the radio stat.

That is the minimum of plumbing/wiring work: Ideally stats everywhere
feeding zone valves all wired back to the boiler is what you want, but
in practice its a hard way to retrofit stuff

The problem with the system I have described is when e.g. the radio stat
is set to a higher temp than the TRVs in that room..perhaps the answer
is to not have TRV's in that room at all..but then how to turn that room
down?

I don;t think there is a perfect answer..you will have to juggle the
complexities yourself

The Natural Philosopher

unread,
Jun 27, 2007, 12:44:17 PM6/27/07
to
Roger Mills wrote:
> In an earlier contribution to this discussion,
> Mike Barnard <m.barnard...@thunderin.co.uk> wrote:
>
>> Hi all.
>>
>> Any CH design guru's aid me in my small dilemma please?
>>
>> I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
>> CH at all untill a couple of years ago when I put a new combi boiler
>> in [1]. I also put a couple of rads in. It was not a complete system,
>> DHW was what I needed mostly. Now the time has finally come to finish
>> the job.
>>
>> The dilemma is whether to zone off the rear two rooms upstairs. The
>> bathroom and bedroom 2 are north facing and in winter they can be much
>> colder than the rest of the house. The thremostat and timing controls
>> are in the open plan lounge; see description below. If the lounge is
>> nice and toasty, then the thermostat will not be telling the boiler to
>> fire up. Therefore the water in the pipes will not be heated and
>> under circulation. No matter how far the TRV's in these rooms open
>> they will recieve no heat.
>>
>
> With a properly designed and balanced system (with radiators of an
> appropriate size in each room/space to balance the heat loss - and with the
> lockshields adjusted to give the same temperature differential across each
> radiator) there's no reason why one room should be significantly hotter or
> colder than any other.

There speaks a man of theory..with respect Roger, in the real world, in
my north rooms when the north wind blows, so does your theory. MUCH more
heatloss from them then...

>
> Zoning comes into its own if you want to heat different parts of the house
> at different times. Otherwise there's not all that much point. If it's easy
> to do, do it anyway - because it gives slightly better control over
> different areas (with a room stat for each area) - but if it's a pain,
> plumbing-wise, don't bother.


If I had my time again I'd zone every single room. With a motorised
valve, and run a shitload of cables back to the timer and pumps etc.

We have a lot of rooms we don't use all the time, and it would be far
more economical to simply flick a switch and have them go to 'frost
stat' settings when not in use.

The Natural Philosopher

unread,
Jun 27, 2007, 12:46:25 PM6/27/07
to
NoSpam wrote:

> I re-did our heating a while ago and split it into 3 zones: downstairs,
> upstairs (less bathrooms), bathrooms+airing_cupboard+workshop. There
> were a number of people saying it was a waste of effort because of the
> open staircase. In practise it's been great. If I'm working at home
> during the day I have the downstairs heating on and the upstairs stays
> cold. The only regret is that I didn't add a fourth zone for just the
> office.
>

My office has so many computers in it, plus a PABX and a dist amp for
TV, and canners/printers/hubs and routers..that it stays toasty warm
whatever the weather.

I agree that the more zones the better, frankly. Energy costs are rising
and it is starting to be a lot easier to justify the initial outlay.


> Dave

Roger Mills

unread,
Jun 27, 2007, 2:46:29 PM6/27/07
to
In an earlier contribution to this discussion,
The Natural Philosopher <a@b.c> wrote:

>
> If I had my time again I'd zone every single room. With a motorised
> valve, and run a shitload of cables back to the timer and pumps etc.
>
> We have a lot of rooms we don't use all the time, and it would be far
> more economical to simply flick a switch and have them go to 'frost
> stat' settings when not in use.

It would certainly be nice to have an S++++ system, with a programmable stat
in every room - so as to be able to heat each room only when needed. You
could probably do it without too much plumbing by using (don't know the
correct description) things like TRVs with little heaters in them to turn
individual rads on and off by remote control. Would need a lot of wiring
though, and I don't know whether these things have secondary contacts which
close when the valve is open - like a proper 2-port zone valve.

Such a system would be a nightmare to programme though unless your room
usage followed a very regular pattern. Even then, you'd have to tell each
individual stat about things like going on holiday for X days. Really needs
to be programmable from a single point - with the ability to apply global
settings to all stats in one go - but I'm not sure how to go about that. I
don't really want to run a dedicated PC *just* the operate the heating!

Lurch

unread,
Jun 27, 2007, 2:49:10 PM6/27/07
to
On Wed, 27 Jun 2007 19:46:29 +0100, "Roger Mills"
<watt....@googlemail.com> mused:

>In an earlier contribution to this discussion,
>The Natural Philosopher <a@b.c> wrote:
>
>>
>> If I had my time again I'd zone every single room. With a motorised
>> valve, and run a shitload of cables back to the timer and pumps etc.
>>
>> We have a lot of rooms we don't use all the time, and it would be far
>> more economical to simply flick a switch and have them go to 'frost
>> stat' settings when not in use.
>
>It would certainly be nice to have an S++++ system, with a programmable stat
>in every room - so as to be able to heat each room only when needed. You
>could probably do it without too much plumbing by using (don't know the
>correct description) things like TRVs with little heaters in them to turn
>individual rads on and off by remote control. Would need a lot of wiring
>though, and I don't know whether these things have secondary contacts which
>close when the valve is open - like a proper 2-port zone valve.
>

You can get mini valves that can be fitted to each rad. Not exactly
sure where you would source the as I've never looked tbh.

>Such a system would be a nightmare to programme though unless your room
>usage followed a very regular pattern. Even then, you'd have to tell each
>individual stat about things like going on holiday for X days. Really needs
>to be programmable from a single point - with the ability to apply global
>settings to all stats in one go - but I'm not sure how to go about that. I
>don't really want to run a dedicated PC *just* the operate the heating!

You can get commercial heating controls that could do all that with
relative ease, and mostly low voltage for sensors in the rooms rather
than programers.
--
Regards,
Stuart.

John Rumm

unread,
Jun 27, 2007, 3:07:22 PM6/27/07
to
Mike Barnard wrote:

> The dilemma is whether to zone off the rear two rooms upstairs. The
> bathroom and bedroom 2 are north facing and in winter they can be much
> colder than the rest of the house. The thremostat and timing controls
> are in the open plan lounge; see description below. If the lounge is
> nice and toasty, then the thermostat will not be telling the boiler to
> fire up. Therefore the water in the pipes will not be heated and
> under circulation. No matter how far the TRV's in these rooms open
> they will recieve no heat.

One simple solution would be to change the stat for a programmable
wireless one and situate it in the cold bedroom. Balance the system so
that all is well when there are no external influences such as cold
north winds etc. Fit TRVs everwhere else. That way the stat will call
for heat until the coldest rooms are heated, and the TRVs will prevent
the warmer rooms overheating.


--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

Ed Sirett

unread,
Jun 27, 2007, 3:54:39 PM6/27/07
to

>
>
>
>

> [1] Worcester Bosch Greenstar R35HE Plus. What a mouthful. As a
> part of putting in a new kitchen, losing an airing cupboard and a wall
> and associated HW tank and plumbing.


It's probably not worth zoning. What you need is to make sure that the hot
area have TRV's and the coldest area doesn't.

If you can make sure the hall way is the coolest area then you can have
the thermostat there where it is convenient to put on/off when you come
in/go out.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs here: http://www.makewrite.demon.co.uk/GasFittingStandards

fred

unread,
Jun 27, 2007, 4:12:18 PM6/27/07
to
In article <6qm4831c3qj3f6m8c...@4ax.com>, Mike
Barnard <m.barnard...@thunderin.co.uk> writes

>Domestic CH - to zone or not to zone...
>
Highly recommended :-D

http://i7.tinypic.com/4yam5x4.jpg
--
fred
Plusnet - I hope you like vanilla

John Stumbles

unread,
Jun 27, 2007, 4:17:12 PM6/27/07
to
On Wed, 27 Jun 2007 19:49:10 +0100, Lurch wrote:

> You can get mini valves that can be fitted to each rad. Not exactly
> sure where you would source the as I've never looked tbh.

Honeywell does a system with some sort of motorised rad valves (bulky and
look sh1t IMNSHO). I don't know how they control it all.

Some moons ago I adapted TRVs by glueing PCB-mounting resistors onto the
sensing elements so that by applying 12V to the resistor the valve would
turn off. I planned to control it all by some custom controller, but never
got the Tuits to make it happen :-(

--
John Stumbles

Fundamentalist agnostic

Graeme

unread,
Jun 27, 2007, 4:16:17 PM6/27/07
to
In message <6qm4831c3qj3f6m8c...@4ax.com>, Mike Barnard
<m.barnard...@thunderin.co.uk> writes
>

>The dilemma is whether to zone off the rear two rooms upstairs.

I cannot answer this from a DIY perspective, because I didn't do ours,
but, having had it done, I think it is wonderful. We have four entirely
independent timers, controlling the heating for three areas, plus hot
water, all powered by a conventional oil fired boiler. Different parts
of the house are heated at different times, to suit our needs. The
times can be overridden, of course. Different times for each day of the
week, if required. Yes, there are TRVs on the rads, which help, and in
theory we could run around adjusting them, but who does?

The only downside is reminding the family that hot air rises - it is
fairly pointless having just the downstairs heating on, with all the
bedroom doors wide open :-)

--
Graeme

Mike Barnard

unread,
Jun 27, 2007, 5:22:01 PM6/27/07
to
On Wed, 27 Jun 2007 14:14:24 +0100, Mike Barnard
<m.barnard...@thunderin.co.uk> wrote:

>Any CH design guru's aid me in my small dilemma please?

>I have a 1960's mid terrace Wimpy (spit) three bed house. It had no

Thanks for all the inputs. Excuse me if I don't reply to each post
individually.

I certaintly agree in the idea of zoning in larger houses, but this is
a small 3 bed terrace house. No room at all to supply pipework to
each rad! And I'll have to cross many floor joists so I don't want to
cut too many pipe holes in either.

So, a couple more questions if I may.

1. Can I have a common return to the boiler or will that cause
problems?

2. Are there any websites that show the theories behind zoning? Yes,
I have googled and found many sites seling valves, but no tech guides.
Nothing in the FAQ either.

3. Should I just do the two north facing rooms?

4. Or three zones... North facing up, south facing up and downstairs?

5. Or one zone up, one down...

6. What size pipes can I get away with if I'm only doing a couple of
rads?

Anything else of a practical nature? Regs?

Again, many thanks.

fred

unread,
Jun 27, 2007, 6:00:23 PM6/27/07
to
In article <3ok5831rrpprif73q...@4ax.com>, Mike Barnard
<m.barnard...@thunderin.co.uk> writes

>On Wed, 27 Jun 2007 14:14:24 +0100, Mike Barnard
><m.barnard...@thunderin.co.uk> wrote:
>
>>Any CH design guru's aid me in my small dilemma please?
>
>>I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
>
>Thanks for all the inputs. Excuse me if I don't reply to each post
>individually.
>
>I certaintly agree in the idea of zoning in larger houses, but this is
>a small 3 bed terrace house. No room at all to supply pipework to
>each rad! And I'll have to cross many floor joists so I don't want to
>cut too many pipe holes in either.
>
Although I have chosen to centralise the controls and run separate feeds (1
feed/return pair per room) there is no need for you to do the same, you can
run a live backbone throughout the house (2 pipes) and place the controls
where they are needed. I would suggest though that you make the controls
accessible with the minimum of fuss as there will be a time when you need
to access them in (and without) anger. If you can make splits off the
backbone in places like airing or other cupboards then do so. Be sure to
insulate the backbone feed and return (at least) as there is no point in
heating the rest of the house if you're just fending off a bit of winter chill in
the master bedroom overnight.

>So, a couple more questions if I may.
>
>1. Can I have a common return to the boiler or will that cause
>problems?

Separate paths for feed and return can run into problems but see above for
the alternative.

>2. Are there any websites that show the theories behind zoning? Yes,
>I have googled and found many sites seling valves, but no tech guides.
>Nothing in the FAQ either.

I don't think so, nobody does this, they think it is too hard.

>3. Should I just do the two north facing rooms?
>
>4. Or three zones... North facing up, south facing up and downstairs?
>
>5. Or one zone up, one down...
>

4 zoning would seem like a reasonable split, 2 up & 2 down. Reasoning
downstairs being why heat the kitchen at all when you're watching telly?
Upstairs is probably less in need of a split but it shouldn't be too hard to
do. Separate zones really are superior to the sort of results you get with
TRVs.

>6. What size pipes can I get away with if I'm only doing a couple of
>rads?

Depends how big the rads are of course :-), but 15mm to 2 rads off a
22mm backbone would be safe.

>
>Anything else of a practical nature? Regs?

Each room needs a control, whether it be TRVs or stat.

Do it, you won't regret it.

Frank Erskine

unread,
Jun 27, 2007, 6:14:05 PM6/27/07
to
On Wed, 27 Jun 2007 22:00:23 GMT, fred <n...@for.mail> wrote:

>Plusnet - I hope you like vanilla

I *love* (real) vanilla :-)

--
Frank Erskine

fred

unread,
Jun 27, 2007, 7:04:30 PM6/27/07
to
In article <m7o583h2t4mlrv89o...@4ax.com>, Frank
Erskine <frank....@btinternet.com> writes

>On Wed, 27 Jun 2007 22:00:23 GMT, fred <n...@for.mail> wrote:
>
>>Plusnet - I hope you like vanilla
>
>I *love* (real) vanilla :-)
>
But Plusnet is that crappy frozen vegetable whey vanilla that Tesco sell in
blue striped gallon tubs, bet you wouldn't touch that ;-)
--
fred

auct...@sheldononline.co.uk

unread,
Jun 28, 2007, 3:45:01 AM6/28/07
to
On Jun 27, 7:46 pm, "Roger Mills" <watt.ty...@googlemail.com> wrote:
> In an earlier contribution to this discussion,

I'm looking at doing exactly that in a project - using actuator
valves and individual room stats. It's not that hard - an actuator on
every radiator instead of a TRV. Each one links to a thermostat in the
room and all the stats link down to a wiring box. I'll then use a
central controller from <http://www.heatmisershop.co.uk/
Heatmiser_MC__Colour_TouchPad-p-16143.html> (their stats look good
too, but I'll use different actuators. The ones for under floor
heating work - they fit onto a TRV body)

Looks like an ideal system. It's not that cheap, but the plumbing is
done as a single zone, so there is a saving there, and the wiring is
simple enough. Can be done wirelessly, but that puts the price up.

A

David Hansen

unread,
Jun 28, 2007, 3:47:59 AM6/28/07
to
On Wed, 27 Jun 2007 19:46:29 +0100 someone who may be "Roger Mills"
<watt....@googlemail.com> wrote this:-

>It would certainly be nice to have an S++++ system, with a programmable stat
>in every room - so as to be able to heat each room only when needed. You
>could probably do it without too much plumbing by using (don't know the
>correct description) things like TRVs with little heaters in them to turn
>individual rads on and off by remote control. Would need a lot of wiring
>though, and I don't know whether these things have secondary contacts which
>close when the valve is open - like a proper 2-port zone valve.

Depending on the arrangement of the house and occupancy one might be
able to do almost the same with three zones. Public rooms, bedrooms
and rooms which are on whenever either or both of the first two is
on. For each of the first two there is a programmer and valve. Other
rooms have thermostatic valves.

The on and off times for each zone would involve the bedrooms being
on first and last thing. The public rooms would be on in the
evening, but go off before the bedrooms. Precise details would
depend on occupancy.

Rooms which were not in use, some bedrooms and a dining room for
example, would be set back via the thermostatic valve.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Roger

unread,
Jun 28, 2007, 4:14:33 AM6/28/07
to
The message <MVPzZHAd4tgGFwyK@y.z>
from fred <n...@for.mail> contains these words:

> >3. Should I just do the two north facing rooms?
> >
> >4. Or three zones... North facing up, south facing up and downstairs?
> >
> >5. Or one zone up, one down...
> >
> 4 zoning would seem like a reasonable split, 2 up & 2 down. Reasoning
> downstairs being why heat the kitchen at all when you're watching telly?
> Upstairs is probably less in need of a split but it shouldn't be too hard to
> do. Separate zones really are superior to the sort of results you get with
> TRVs.

I initially resisted the idea that I would benefit from zoning as I have
an open staircase leading from the living room but I eventually weakened
and have not subsequently regretted it. FWIW I have effectively 3 zones.
Downstairs with the programmable stat in the living room, upstairs with
the programmable stat in the main bedroom and the bathroom where the
radiator (with a TRV) is on the boiler bypass circuit and is thus
supplying needed heat whenever the boiler runs. There is an automatic
valve on the bypass circuit which can operate when the bathroom TRV is
closed.

--
Roger Chapman

The Natural Philosopher

unread,
Jun 28, 2007, 6:27:57 AM6/28/07
to
Roger Mills wrote:
> In an earlier contribution to this discussion,
> The Natural Philosopher <a@b.c> wrote:
>
>> If I had my time again I'd zone every single room. With a motorised
>> valve, and run a shitload of cables back to the timer and pumps etc.
>>
>> We have a lot of rooms we don't use all the time, and it would be far
>> more economical to simply flick a switch and have them go to 'frost
>> stat' settings when not in use.
>
> It would certainly be nice to have an S++++ system, with a programmable stat
> in every room - so as to be able to heat each room only when needed. You
> could probably do it without too much plumbing by using (don't know the
> correct description) things like TRVs with little heaters in them to turn
> individual rads on and off by remote control. Would need a lot of wiring
> though, and I don't know whether these things have secondary contacts which
> close when the valve is open - like a proper 2-port zone valve.
>
> Such a system would be a nightmare to programme though unless your room
> usage followed a very regular pattern. Even then, you'd have to tell each
> individual stat about things like going on holiday for X days. Really needs
> to be programmable from a single point - with the ability to apply global
> settings to all stats in one go - but I'm not sure how to go about that. I
> don't really want to run a dedicated PC *just* the operate the heating!

No need to program anything. Just go into a room, switch it ON, forget
timers by and large, and if its too cold on comes the heating.

You just 'wire OR' the motorised valves..(connect em in parallel)

John Rumm

unread,
Jun 28, 2007, 10:31:15 AM6/28/07
to
fred wrote:
> In article <m7o583h2t4mlrv89o...@4ax.com>, Frank
> Erskine <frank....@btinternet.com> writes
>> On Wed, 27 Jun 2007 22:00:23 GMT, fred <n...@for.mail> wrote:
>>
>>> Plusnet - I hope you like vanilla
>> I *love* (real) vanilla :-)
>>
> But Plusnet is that crappy frozen vegetable whey vanilla that Tesco sell in
> blue striped gallon tubs, bet you wouldn't touch that ;-)

Which would suggest the most ISPs a flogging you a bowl of frozen lard
then!

(for all their occasional stuff ups, they do manage to get a number of
things right that seems to permanently elude the others)

Roger Mills

unread,
Jun 28, 2007, 11:52:56 AM6/28/07
to
In an earlier contribution to this discussion,
The Natural Philosopher <a@b.c> wrote:

> Roger Mills wrote:
>>
>> Such a system would be a nightmare to programme though unless your
>> room usage followed a very regular pattern. Even then, you'd have to
>> tell each individual stat about things like going on holiday for X
>> days. Really needs to be programmable from a single point - with the
>> ability to apply global settings to all stats in one go - but I'm
>> not sure how to go about that. I don't really want to run a
>> dedicated PC *just* the operate the heating!
>
> No need to program anything. Just go into a room, switch it ON, forget
> timers by and large, and if its too cold on comes the heating.
>
> You just 'wire OR' the motorised valves..(connect em in parallel)

OK - so when you go on holiday for a fortnight in winter, how do you tell it
just to provide frost protection until the day *before* your return, and
*then* revert to the normal cycle in order to ensure that you return to a
warm house?

I can easily do that with my (single heating zone) system, controlled by a
CM67 programmable thermostat.

Andy Hall

unread,
Jun 28, 2007, 1:16:50 PM6/28/07
to
On 2007-06-27 19:49:10 +0100, Lurch <myrea...@sjwelectrical.co.uk> said:
>>
>>
> You can get mini valves that can be fitted to each rad. Not exactly
> sure where you would source the as I've never looked tbh.


Sauter make them.


There are two basic types, both intended to sit on a TRV valve base in
place of the normal manual head.

- Thermal drive e.g. AXT 111. This is basically a commercial
version of John Stumbles' idea. They work reasonably well if one is
happy with on and off control - fully open or fully closed. I tried
to make one do proportional control and partly open the valve, but it
wasn't all that successful - very non linear and variation between two
units, so would have to be individually calibrated. However, they are
about the same size as a TRV head

- Motor drive e.g. AXM 117S. These have a positioner and can be
controlled by a DC voltage of 0-10v. They seem to be consistent as
well. The motor body isw a bit larger but not obtrusive if the
overhanging piece is pointed back towards the wall.

ARWadsworth

unread,
Jun 28, 2007, 1:45:02 PM6/28/07
to

"Graeme" <Gra...@nospam.demon.co.uk> wrote in message
news:Btx8RZkR...@nospam.demon.co.uk...

The you have teenagers or cats. One leaves the door open, the other expects
the door to be left open.

Adam

dennis@home

unread,
Jun 28, 2007, 2:56:19 PM6/28/07
to

"Roger Mills" <watt....@googlemail.com> wrote in message
news:5ei3qbF...@mid.individual.net...

> OK - so when you go on holiday for a fortnight in winter, how do you tell
> it just to provide frost protection until the day *before* your return,
> and *then* revert to the normal cycle in order to ensure that you return
> to a warm house?
>
> I can easily do that with my (single heating zone) system, controlled by a
> CM67 programmable thermostat.

I zoned my house when I installed CH 25 years ago.
Five zones five programmable stats (well they were timers and stats 25 years
ago but I replaced them with more advanced digital timer stats a few years
ago.
Works very well and there is no change to the settings between winter and
summer.
I just wish the valves were more reliable as I have had to replace all of
them now.


Graeme

unread,
Jun 28, 2007, 3:57:52 PM6/28/07
to
In message <ysSgi.13371$p8....@text.news.blueyonder.co.uk>, ARWadsworth
<adamwa...@blueyonder.co.uk> writes

>"Graeme" <Gra...@nospam.demon.co.uk> wrote in message
>news:Btx8RZkR...@nospam.demon.co.uk...
>>
>> The only downside is reminding the family that hot air rises - it is
>>fairly pointless having just the downstairs heating on, with all the
>>bedroom doors wide open :-)
>
>The you have teenagers or cats. One leaves the door open, the other
>expects the door to be left open.
>
<Grin> Almost - a wife, a six year old who knows everything, and two
cats :-)
--
Graeme

Andy Hall

unread,
Jun 28, 2007, 4:38:17 PM6/28/07
to

Wait until the six year old becomes a teenager. They will never know
as much again.


Andrew Gabriel

unread,
Jun 29, 2007, 2:25:36 AM6/29/07
to
In article <6qm4831c3qj3f6m8c...@4ax.com>,
Mike Barnard <m.barnard...@thunderin.co.uk> writes:
> Hi all.

>
> Any CH design guru's aid me in my small dilemma please?
>
> I have a 1960's mid terrace Wimpy (spit) three bed house. It had no
> CH at all untill a couple of years ago when I put a new combi boiler
> in [1]. I also put a couple of rads in. It was not a complete system,
> DHW was what I needed mostly. Now the time has finally come to finish
> the job.
>
> The dilemma is whether to zone off the rear two rooms upstairs. The
> bathroom and bedroom 2 are north facing and in winter they can be much
> colder than the rest of the house. The thremostat and timing controls
> are in the open plan lounge; see description below. If the lounge is
> nice and toasty, then the thermostat will not be telling the boiler to
> fire up. Therefore the water in the pipes will not be heated and
> under circulation. No matter how far the TRV's in these rooms open
> they will recieve no heat.

Well that's resolvable by matching radiator sizes to heatloss
in each room, which should have been done anyway. The room
with the thermostat could be relatively slightly undersized
to ensure other rooms are normally all up to temperature before
the thermostat switches off.

However, to go back to your main point, I installed central
heating in an end-terrace house 5 years ago. I zoned it and
I don't regret that one bit. I split it into 3 zones;
downstairs, upstairs, and bathroom. The bathroom sticks out
the back of the house and was prone to be cold and takes a
long time to warm up. The bathroom zone is simply the logical
OR of the upstairs and downstairs zones, i.e. the bathroom
heating is on if either upstairs or downstairs heating is on.

Some things to bear in mind...

A small zone is likely to have insufficient heat output to
absorb all the power of a modulating boiler even at lowest
power output, so you will get boiler cycling. Some modulating
boilers, particularly condensing with a system designed for
efficient low flow temperature, are not all that good when
cycling at low temperature. Even a medium sized zone will
have this issue when only low heat output is required, and
you will end up with periods where multiple medium sized
zones end up taking turns with heating demand resulting in
a long period of cyclic boiler running where fewer/single
zone would avoid this. My own designed heating controller
attempts to avoid this, but I don't know if there are any
multi-zone commercial heating controllers which do that
(and multiple single zone ontrols could not do that).

If you are intending to be able to operate the system with
some zones switched off (or frost setting), remember to allow
for the heatloss to a cold room from a warm room on a different
zone, bearing in mind that rooms are often not well thermally
insulated from each other. This is particularly important for
upstairs verses downstairs zones. Often much of the upstairs
heating comes from downstairs through the floor, but if you
make that normal assumption in a heatloss calculator, you will
find it difficult to heat the upstairs alone if downstairs is
cold and not contributing.

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

John Stumbles

unread,
Jun 29, 2007, 9:55:26 AM6/29/07
to
On Wed, 27 Jun 2007 22:22:01 +0100, Mike Barnard wrote:

> 2. Are there any websites that show the theories behind zoning? Yes,
> I have googled and found many sites seling valves, but no tech guides.
> Nothing in the FAQ either.

What does this NOT tell you that I should add to it?
http://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Controls_and_Zoning


--
John Stumbles

I used to be forgetful but now I ... um ....

Doctor Drivel

unread,
Jun 29, 2007, 12:00:55 PM6/29/07
to

"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:4684a5e0$0$648$5a6a...@news.aaisp.net.uk...

This is where a thermal store comes in. Take all the zones from the water
store and the boiler only heats the store with one long efficient burn.

ARWadsworth

unread,
Jun 29, 2007, 2:01:29 PM6/29/07
to

"Andy Hall" <an...@hall.nospam> wrote in message
news:4684...@nt1.hall.gl...

And I bet this bugger only came home as the credit card in the top photo had
expired
http://news.bbc.co.uk/1/hi/england/hampshire/6253634.stm

Adam

Mike Barnard

unread,
Jul 3, 2007, 11:33:12 AM7/3/07
to
On Fri, 29 Jun 2007 13:55:26 GMT, John Stumbles
<john.s...@ntlworld.com> wrote:

>On Wed, 27 Jun 2007 22:22:01 +0100, Mike Barnard wrote:
>
>> 2. Are there any websites that show the theories behind zoning? Yes,
>> I have googled and found many sites seling valves, but no tech guides.
>> Nothing in the FAQ either.
>
>What does this NOT tell you that I should add to it?
>http://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Controls_and_Zoning

Sorry about the delay in replying, I missed this post. How about the
fact that I didn't know it existed? :) The FAQ isn't the Wiki... is
it? I went here...

http://www.diyfaq.org.uk/

and to here...

http://www.diyfaq.org.uk/plumbing/heating/heatingsystems.html

Should links be updated?

Reply all
Reply to author
Forward
0 new messages