# Central Heating - Multiple Zones?



## Dibs-h (19 Sep 2011)

I've read posts here of folk separating the heating at home into 2 (or more) zones. Say 1 for the rads upstairs and another for the downstairs. I can see the logic for this - why heat half the house when it's empty, etc. and given that our annual gas consumption is somewhat eye watering - I'm been meaning to look into this for a while.

Whilst surfing the web - looking at programmable room stats, wired vs wireless, etc., I came across the following article,

http://www.telegraph.co.uk/property/pro ... decay.html

which made me pause, especially the following paragraph,



> As with many energy-saving ideas, this one has been promoted by the Government in response to current “climate change” hysteria, without regard to the bigger picture. Repairing condensation-damaged decorations will consume far more money and energy than that saved by reduced fuel bills. In my opinion,* it would better for your wallet and the environment for you to keep the whole house heated and therefore above dewpoint temperature*.



Any thoughts\advice? I have come across similar mentions before.

Until this point - I was erring down the road of a 2 wireless programmable room stats and a pair of 2 port valves (or possibly getting away with a single 3 port valve that does mid-position). With the upstairs bathroom rad as the the bypass (i.e. on all the) as the bathroom is on the other side of the wall where the 22mm heating pipes drop down.

Cheers

Dibs


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## sparkymarky (19 Sep 2011)

i would ignore jeff howells article, it`s all well and good writing a article which is his own opinion, but the article doesn`t take into consideration the different types of houses cob, concrete block, cavity wall insulation, vents above windows, double glazing ect ect... similar single minded articles were written stating that lower sulphur heating oil would cause aga`s and rayburns to go wrong, which is a load of rubbish there was alot more variable factors. 

i would defiantly consider a two zone system for upstairs and downstairs (most new houses are these days anyway with underfloor heating) however i wold forget about programmable room thermostats just use a normal wireless room stat ideally a honeywell (like this one http://www.ebay.co.uk/sch/i.html?_from= ... Categories its very reliable and doesn`t require linking to the base unit) then use a dual channel programmer to control the zones. 

i would stay away from y plan zone vales, fit individual zone valves when they go wrong it will be easier and cheaper to repair them, the wirings is also easier to configure.

go for a auto bypass don`t use a radiator they only cost around £15 and they limit central heating throttle noise through radiators as the trv`s close down. 

if you need any advice on wiring of plumbing configurations just ask.

hope this helps.

cheers, mark.


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## Dibs-h (19 Sep 2011)

sparkymarky":3vvpqkct said:


> i would ignore jeff howells article, it`s all well and good writing a article which is his own opinion, but the article doesn`t take into consideration the different types of houses cob, concrete block, cavity wall insulation, vents above windows, double glazing ect ect... similar single minded articles were written stating that lower sulphur heating oil would cause aga`s and rayburns to go wrong, which is a load of rubbish there was alot more variable factors.
> 
> i would defiantly consider a two zone system for upstairs and downstairs (most new houses are these days anyway with underfloor heating) however i wold forget about programmable room thermostats just use a normal wireless room stat ideally a honeywell (like this one http://www.ebay.co.uk/sch/i.html?_from= ... Categories its very reliable and doesn`t require linking to the base unit) then use a dual channel programmer to control the zones.
> 
> ...



Mark

Cheers for the advice. After posting, I spoke tomy tame'ish heating chap and he suggested to not be tight and fit a pair of 2 port valves for exactly the same reasons you stated.

I had thought about 2 wireless room stats as one could have the downstairs one in the room in which we are in, but having come across the advice that the room in which the wireless stat is in, not to have TRV, so wondered how you could take it from room to room. During our discussion it was realised that doing this could end up with more problems than it solves.

In the end going to go for a wired stat (non program) upstairs, as it's dead easy to run the cable to the boiler in the loft and a plain wireless one on the ground floor (to save the wireless headache & again a non-prgram one).

Cheers for the auto Bypass advice. We kind of want the upstairs bathroom on, irrespective of whether the downstairs rads are on, upstairs are on or both. Does that mean fitting a bypass valve as well?

Cheers

Dibs


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## RogerS (19 Sep 2011)

Dibs..my first reaction when I read the DT article was 'cock'. Sparkymarky puts it much better than me. I'd definitely go down that route...the downside is going to be how easy is it for you to split the pipes into two zones? You might also like to consider one of these http://www.totalenergycontrols.co.uk/p/ ... master.php

Last winter we pulled the house temperature right down and use a wireless thermostat in the sitting room while we're there in the evening. Gives just enough background heating to the rest of the house while the heating system is feeding the sitting room. I've got a legacy thermostat/timer upstairs and use that to fire up a bit of heat into the house first thing in the morning. Any localised heat we need in a room that's not used very much is provided by a quick burst of electric fan heater. With ch oil at over 55p a litre currently, i can see extra sweaters. The open fire in the sitting room also keeps the house warm burning offcuts from the workshop.

Check out one of these to see where you are losing heat. http://www.youtube.com/watch?v=xpifuiVpv2w

Roger


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## Lons (19 Sep 2011)

I don't see the point Dibbs. We have TRVs on every rad (15 of them) except the en-suite towel rad and just adjust them as necessary. You have to keep the bedroom doors shut whatever you do so for the sake of a few seconds it works for us.
Whoever is up first turns it down and in the evening, wife goes and brushes teeth, dressing gown on etc about an hour before retiring so she re-adjusts the trvs - voila

Just my opinion and there are only 2 of us in the house which makes it easier but I'm a tight git, we don't have gas so heating is oil (ouch) and our bills are within reason in the current climate.

Bob


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## Digit (19 Sep 2011)

That DT comment is rubbish, fine, keep above Dew point, I agree, but he infers that that can only be acheived with unoccupied room temps at the same comfort level as occupied rooms.

Roy.


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## wobblycogs (19 Sep 2011)

At last a chance to repay some of that great advice you've given me over the last couple of years, Dibs.

We've mostly fitted, and by that I mean we've actually done all the plumbing and wiring, a 13 zone heating system built around these programmable room thermostats from John Guest: http://www.speedfitufh.co.uk/network-programmable-room-stat.php. The system is fitted in a detached 6 bedroom Georgian town house which leaks heat like a sieve. For the most part every room is on it's own thermostat and can therefore be controlled individually.

So, why did we do it? When we bought the house there were only two of us (so we wouldn't be using all the house) and I work from home full time. Both of those factors said to us that what we really wanted was a way to heat just a portion of the house and at different times of the day. In the week I want just the office warm all day and in the evenings we wanted just the living room and bedroom warmed. We also wanted to optionally heat other rooms on demand.

Last winter was the first year we've lived with the system and, of course, it was one of the coldest on record. I'm really pleased to say that it worked better than I could possibly have dreamt. Our heating bill was comparable to my parents 10 year old, insulated up to the eye balls, house which has a standard heat everywhere system fitted. Better than that though we were able to just dial up the temperature in a room when we wanted much like you would turn on the light. I rattled out some calculations based on how much energy I think we would have used to get the same result but using a standard whole house heating installation and the system will easily pay for itself this winter.

Down sides? You'll probably have to fit it yourself as finding a plumber that knows about it is basically impossible. When we put in ours the only thermostats available were wired which means a lot of cable runs, I think you can get wireless now though. If it's very cold outside it can take a while for an unheated room to warm up so a bit of planning ahead may be necessary - was never a problem for us though.

Some things to think about if you go for a system like this... massively over side your radiators for each room, at least 1.5* what the regular calculations recommend. This is because the rooms around you will probably be cold, if they aren't cold the thermostat will fix the over heating anyway. The manifold is chunky and needs a surprising amount of space around it, we screwed up and had to fit it sideways which looks awful but it works.

Would I do it again? For a house like this which is difficult to heat, most definitely. For a modern, well insulated house: no, I'd fit a two zone system.

Oh, as for condensation we just set all the stats in unused rooms to 11 deg C and leave it at that.


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## sparkymarky (19 Sep 2011)

Dibs-h":21ekgh8n said:


> but having come across the advice that the room in which the wireless stat is in, not to have TRV



just take the head off the trv`s or turn the trv up to max then the wireless stat would shut the heating off to perform `boiler interlock`before the trv shut the radiator off. the maximum setting for most trv`s is 28-33 0c air temperature so if your wireless stat is set at 21 0c then it would shut down the heating in the room you are in. 

the advice you have been given is in regards for new buildings, the reason is to show that the heating has interlock and therefore efficient, on existing houses unless you want to sell the house you can do what you like as long as the system suits you and it saves you money. 




Dibs-h":21ekgh8n said:


> We kind of want the upstairs bathroom on, irrespective of whether the downstairs rads are on, upstairs are on or both



why not stick in another zone for the towel rails  you can run the towel rails as bypass`s, i would still recommend for the cost of the auto bypass to install one even if you keep the towel rails on.


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## johnf (19 Sep 2011)

Cut your bills by 60 to 70% put in a ground source heat pump heat the whole building 24 hrs of the day works for us 3000 ft2 of property

Electricity bill for the year looks like £1000 max thats for everything heating hot water cooking lighting .

Then put in solar panels make your own power and the FIT pays the power bill for the next 25 years job done
By the way the ground source heat pump will also pay the RHI subsidy from October 2012


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## Mark A (19 Sep 2011)

we just use the TVR's to adjust the temperature. Still cost over a grand in oil last winter though (stone house :duno: )


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## Dibs-h (19 Sep 2011)

Cheers Chaps for the advice.

Mark - my "tame" heating suggested exactly the same, i.e. take the TRV head off the rad that has the wireless stat in that room. So will be going for that. Will have a chat with my "tame" heating chap about the bypass and\or bathroom circuit. Thankfully he's quite familiar with the piping in our house and cutting the flow to achieve the 2 circuits should be very straightforward (I hope).

Wobbly\Roy - the longer term aim is to fit UFH heating throughout the house fed (primarily) by 2 evacuated tube panels on the workshop\garage room (which is South facing) feeding a thermal store. That will have a large manifold, with something like 10 zones, with each room\zone having it's own programmable room stat. Knowing my luck and work list it might be a couple of years before that happens, so want to cut our current gas bill, which is around 1.5K. I figure that at a cost of no more than £150, I could split the zones and save that cost in the gas bill before the UFH comes in.

Also looking at fitting insulated plasterboard with 2" kingspan on all the exterior walls - this will probably happen in the next 12 months, room\wall at a time - as I am sick of the gas bill. Will mean replacing the original coving on those walls, but as I'm already replicating the coving, as it's missing in a few rooms - no real headache to make up some more (already have the running moulds).

Thanks

Dibs


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## 9fingers (19 Sep 2011)

When I put our central heating in around 1984, I put in two zones. Essentially upstairs and downstairs but the upstairs bathroom was plumbed in to the downstairs circuit with a then rare thermostatic valve and an oversized radiator.
The idea being that there would be scope for convection to the upstairs bathroom when the pump was off due to no demand downstairs.

We have never even switched on the upstairs circuit so in practice there is no need for upstairs heating - apart from the bathroom. Sufficient warm air goes up stairs from the hall.

So maybe it is worth considering what heating requirements you have - I could have saved a lot of time and effort on my installation.

Bob


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## wobblycogs (19 Sep 2011)

Are you planning on fitting UFH to existing wooden floors? 

We took a good long look into ways of doing it and everyone said just don't bother it's more work that it's worth and that included the guys setting the stuff. Every single person we spoke to said that unless you were totally stripping the house back down to joists and brick work it just wasn't worth the effort of trying to fit the pipe work and insulation required.


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## 9fingers (19 Sep 2011)

UFH can be very effective for use with the low grade heat (low temperature) from heat pumps. So yes it does involve a lot of upheaval but with the future incentive schemes that John F mentioned UFH might be appropriate.

Bob


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## Dibs-h (19 Sep 2011)

wobblycogs":1oi67fnp said:


> Are you planning on fitting UFH to existing wooden floors?
> 
> We took a good long look into ways of doing it and everyone said just don't bother it's more work that it's worth and that included the guys setting the stuff. Every single person we spoke to said that unless you were totally stripping the house back down to joists and brick work it just wasn't worth the effort of trying to fit the pipe work and insulation required.



Yes - going to fit it to upstairs wooden floors. Most of the floors will come up as they've butchered over the years. The plan is to fit mahogany parquet (which is sitting in the workshop) on the ground floor, which will mean lifting the floorboards which are in very good condition. These will go upstairs - so if I'm replacing the upstairs floorboards, might as well put the UFH heating down and 2" kingspan to reduce heat losses. The loft hasn't any flooring down - so it's very straightforward to lay it down there.

Not paying labour - allows such follies to be entertained, especially if I have a oversized solar setup. :mrgreen: 

Dibs


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## Lons (20 Sep 2011)

Dibs-h":tolutefl said:


> , so want to cut our current gas bill, which is around 1.5K. Dibs



That seems very high to me Dibs so you clearly need to do something. How old is your boiler / rads?

We have a pretty large house, quite exposed and the winds are bloody cold in Northumberland  but our combined oil and electricity bills are a lot less than that.

Bob


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## Dibs-h (20 Sep 2011)

Lons":1iduy9r1 said:


> Dibs-h":1iduy9r1 said:
> 
> 
> > , so want to cut our current gas bill, which is around 1.5K. Dibs
> ...



Hi Bob

The boiler is a condensing combi about 2 yrs old but the rads are on the whole quite old - at least 15 yrs old. A few I've replaced in the last 2yrs, as 1 rotted thru the one in the living room, was blatantly undersized. Don't want to replace the rest as they heat those rooms fine and with the UFH in a few yrs time - they won't be in long enough to get the payback.

The main problem is that the heating is on 24/7 (or has been over the last 10yrs), even when the house is unoccupied, let alone all of it when the house is occupied.

No room stat as well. So splitting the zones and using 2 room stats should (I hope) make a noticeable difference.

The cause of it is (as is usually the case) - SWIMBO! When we got married yrs ago, gas was alot cheaper so leaving it on all the time - 'cos she preferred it that way, was fine. But with the current prices - obviously not. So thought of the current plan - before we try the "wear a thick jumper\fleece etc. love!"

And as you know - Plan B isn't going to go down well.  

Dibs


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## Lons (20 Sep 2011)

All makes sense Dibs - cheaper to get a new wife? :roll: 

I've got the opposite in that wifie is hot one mitute and cold the next whilst I like a constant comfortable temp though our room thermostat is never above 18 deg.  
I think I'm kept warm by the gallons of coffee I drink :wink: 

I've changed a number of our rads and was astonished at how much hotter they are and much quicker to heat up . Old ones are about 30 years now.

Bob


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## RogerS (20 Sep 2011)

And if anyone is thinking about creating a system like this, do NOT use plastic pipe unless you have one of those gizmo's in the circuit to extract the magnetite out of the water. Otherwise you will find that if you have some circuits that are rarely used...and so have little or zero flow through them...then they will be blocked by magnetite which seems to prefer settling in a plastic pipe compared to copper. DAMHIKT


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## RogerM (20 Sep 2011)

Another fan of dual zone CH here. As I think I've mentioned before, we split upstairs from downstairs, and control the zones with a 3 zone (Up/Down/HW) Horstmann ChannelPlus H37XL series 2 three channel programmer. We were warned off prorammable thermostats by our plumber, and just use 2 wireless Drayton Digistat RF1 thermostats to control each zone. The downstairs one follows us into the lounge in the evening. We just need to ensure that the TRV is turned up, and if the log burner is on the CH turns off downstairs completely. As we don't use the lounge during the day, we turn the TRV right down before we go to bed so that it doesn't come on in the morning. The benefit all gets negated of course if SWMBO goes in to the lounge too draw back the curtains in the morning and leaves the door wide open! #-o 

We keep the TRVs in the spare bedrooms on very low, and have never had any problems with condensation. It is important though to keep the doors upstairs closed during the day and early evening.


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## Dibs-h (20 Sep 2011)

Lons":2lwwg5mi said:


> All makes sense Dibs - cheaper to get a new wife? :roll:
> 
> I've got the opposite in that wifie is hot one mitute and cold the next whilst I like a constant comfortable temp though our room thermostat is never above 18 deg.
> I think I'm kept warm by the gallons of coffee I drink :wink:
> ...



Lons.

Thankfully she is almost entirely self-financing, so can't really complain, other than she keeps adding to my my "work-list."

She, I suspect like a lot of wives, as a knackered thermostat. Middle of summer - 22c and she's cold at night. So on with the thicker duvet and me sweating to death! Can't win really!

Having a bit of a Google on Wireless Room Stats - any recommendations? Don't want to shell out more than required, but don't want to replace it on a regular basis either.

Rog - turning the TRV right up in the room that you are in. That makes sense as to how you ensure you don't get issues with taking the Wireless stat around with you.

Cheers

Dibs


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## RogerM (20 Sep 2011)

We've been very pleased with the Drayton RF1 wireless stats. Very easy to set up and use. I believe they have been superceded now, but I suspect the replacement will be just fine.


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## Eric The Viking (20 Sep 2011)

sparkymarky":2b2vjldv said:


> I would ignore jeff howells article, it`s all well and good writing a article which is his own opinion, but the article doesn`t take into consideration the different types of houses cob, concrete block, cavity wall insulation, vents above windows, double glazing ect ect... similar single minded articles were written stating that lower sulphur heating oil would cause aga`s and rayburns to go wrong, which is a load of rubbish there was alot more variable factors.
> 
> i would defiantly consider a two zone system for upstairs and downstairs (most new houses are these days anyway with underfloor heating) however i wold forget about programmable room thermostats just use a normal wireless room stat ideally a honeywell (like this one http://www.ebay.co.uk/sch/i.html?_from= ... Categories its very reliable and doesn`t require linking to the base unit) then use a dual channel programmer to control the zones.
> 
> ...



Jolly good advice above, in every respect. 

We've got a big place with two heating zones. There are three individual valves (heating, ground floor and bedrooms). The heating has been installed for a few years (about eight, IIRC), and in that time I've had to change the hot water valve (which does the most work) three times. 

The design of these valves is complete rubbish - inherently unreliable: On a 2-port valve, when it's open, a small induction motor is continually energised, pulling against a strong spring. There is a mechanical gearbox, but also metal-on-plastic gearing, and so on. I think they are deliberately designed to fail.

If you can, buy valves from a well-known manufacturer, and that allow the mechanism to be quickly unclipped from the water valve part for replacement. They _will_ fail, but it'll most probably be the electrics.


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## wobblycogs (20 Sep 2011)

I believe the valve you are describing is referred to as a spring return valve - I agree they are a stupid design but it is what's used in most heating systems in the UK.

We have the alternative which is a MOMO valve (motor on, motor off) e.g the valve is motor driven open and closed. As far as I know the only brand you can get in the UK is made by Sunvic. So far we haven't had a problem but a lot of plumbers we've spoken to think MOMO is the work of the devil and they come up with the most preposterous reasons why the valve will fail early. The most common reason is that the motor is powered up twice as often compared to a spring return. That, of course, forgets the fact that with a spring return the motor is full energized and stalled when in the open state! Personally I think most plumbers are just scared of something different as a MOMO requires an additional control wire to be connected.


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## Dibs-h (20 Sep 2011)

wobblycogs":16owgful said:


> I believe the valve you are describing is referred to as a spring return valve - I agree they are a stupid design but it is what's used in most heating systems in the UK.
> 
> We have the alternative which is a MOMO valve (motor on, motor off) e.g the valve is motor driven open and closed. As far as I know the only brand you can get in the UK is made by Sunvic. So far we haven't had a problem but a lot of plumbers we've spoken to think MOMO is the work of the devil and they come up with the most preposterous reasons why the valve will fail early. The most common reason is that the motor is powered up twice as often compared to a spring return. That, of course, forgets the fact that with a spring return the motor is full energized and stalled when in the open state! Personally I think most plumbers are just scared of something different as a MOMO requires an additional control wire to be connected.



I'd much rather have a MOMO valve than one that's energised all the time. Any model number?

Cheers

Dibs


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## Eric The Viking (20 Sep 2011)

wobblycogs":1cl2z3km said:


> Personally I think most plumbers are just scared of something different as a MOMO requires an additional control wire to be connected.



Yup, that's my experience too. For example Microbore is also the spawn of Satan and cannot be mixed with 15mm rad piping, Sir.

I wasn't aware you could get such valves here - good idea. I'll investigate, as anything that improves reliability has to be a good thing.


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## wobblycogs (20 Sep 2011)

This is what we have: http://www.sunvic.co.uk/momo_valves.htm


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## YorkshireDave (20 Sep 2011)

Dibs. Are you saying you're fitting UFH upstairs and simply parquet downstairs? Where is your kingspan going?


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## Dibs-h (20 Sep 2011)

YorkshireDave":1xz0yr21 said:


> Dibs. Are you saying you're fitting UFH upstairs and simply parquet downstairs? Where is your kingspan going?



The UFH will go on all 3 floors (ground, 1st and loft). I plan to nail roofing laths to the side of the joists, say 3.5" down, cut and fit 1/2" ply and sit the 2" kingspan on that. Then run the pipework between the joists and then on the upper 2 floors, lay the floorboards down.

On the ground floor it will be slightly different in that I'll then lay 1/2" ply down over the lot and then parquet over the lot.

In all cases - there will be a dry screed (lightweight) mix between and over the pipes.

Well that's the plan - obviously there will have to be some calculations for the heat transfer etc. and possibly a slight design adjustment for the ground floor. Did the load bearing calcs ages ago and the joists are more than up to the job of the slightly heavier load, i.e. mid span deflections are well within the L/360 or whatever it was.

Dibs


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## Dibs-h (20 Sep 2011)

Mark

I was going to get 2 wireless stats (non program) or 1 wired and 1 wireless, but came across these on Ebay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... _500wt_949

and thought that for the price - I couldn't go wrong. Siemens are a good\quality brand in my eyes - what do you think?

Cheers

Dibs


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## sparkymarky (20 Sep 2011)

Dibs-h":2t9shwu9 said:


> I was going to get 2 wireless stats (non program) or 1 wired and 1 wireless, but came across these on Ebay
> 
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... _500wt_949
> 
> and thought that for the price - I couldn't go wrong. Siemens are a good\quality brand in my eyes - what do you think?



i would generally only recommend honeywell controls for wireless room thermostats, they are one of the main players in the heating controls sector, as a boiler engineer i see a fair few faulty wireless room stats however these have mainly been the sunvic ones i have also replaced a few of the the drayton stats too, if i replace a stat it would be with a honeywell stat because although i know they are more expensive they are a much better quality and i have found so far i haven`t had one fail on me. i mainly fit the honeywell Y6630D1007 purely because of ease of adjusting the temperature on the analog wheel rather than using the digital buttons or controls. i know if you keep an eye out on ebay they can go cheap but i normally buy them from the local merchants for around £60-£65 +vat.

siemens although a quality brand for many household appliances do not specialise in heating controls that perhaps reflects in the quality of heating controls when compared to a danfoss or honeywell product.


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## Dibs-h (22 Sep 2011)

Mark

Got 2 (new) Honeywell Y6630D1007 stats off EBay today for < £80 for the pair. Programmer - I was looking at the following,

http://www.screwfix.com/p/horstmann-cen ... mmer/11225

What do you think?

Dibs

*edit:* had a chat with my "tame" heating chap and he's suggesting the following http://www.screwfix.com/p/siemens-rwb29 ... mmer/65118 as you can advance both channels, whereas you can only advance 1 channel on the Horstmann.


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## sparkymarky (22 Sep 2011)

this is one of the best programmers available on the market at the moment (http://www.ebay.co.uk/itm/honeywell-st9 ... 500wt_1156)

the honeywell st9400 can +1 hour to +3 hour it can also be advanced. the time is also atomic locked so it doesn`t need the time setting, it also changes automatically for summer / winter times.

hth, mark.


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## Dibs-h (22 Sep 2011)

sparkymarky":nsl93hvv said:


> this is one of the best programmers available on the market at the moment (http://www.ebay.co.uk/itm/honeywell-st9 ... 500wt_1156)
> 
> the honeywell st9400 can +1 hour to +3 hour it can also be advanced. the time is also atomic locked so it doesn`t need the time setting, it also changes automatically for summer / winter times.
> 
> hth, mark.




Cheers Mark

Bought a pair of Sunvic Momo 2 port valves and the Siemens WRB29, unfortunately saw your post a bit on the late side.  

Now try to get my head round the wiring which hopefully shouldn't be too much of a headache. Will let you know how I get on.

Cheers

Dibs


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## OLD (23 Sep 2011)

This wiring guide may be of some use quite easy to adapt to other makes.
http://www.honeywellukwater.com/downloads/General-Information/


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## Eric The Viking (23 Sep 2011)

I tidied ours up (3 timers + 3 valves) with a couple of these:





It was quicker than drilling plastic boxes, etc., and now I can find the circuits and test them easily, if needs be. The original installation was a rats' nest.

Someone mentioned the mo-mo valves use an extra wire -- does that change the basic circuit, or is it for a limit microswitch of some sort? They do sound like a good idea...


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## Dibs-h (23 Sep 2011)

Eric The Viking":qhwlwvqt said:


> Someone mentioned the mo-mo valves use an extra wire -- does that change the basic circuit, or is it for a limit microswitch of some sort? They do sound like a good idea...



Looking at the wiring diagram - they seem to have an extra wire (5 in total). The 5th wire is Green\Yellow and goes to earth. Cheers for the wiring centre advice - will be looking to get something similar.

Here's a picture of the wiring diagram,







HIH

Dibs


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## YorkshireDave (23 Sep 2011)

If it's running costs that are the motivator here, zoning will contribute but putting an optimiser and compensator in will save you even more. An optimiser is a device that looks at what time you wish the house to be at operating temp, looks at inside and outside temps and then calculates exactly when the boiler should start so that no fuel is wasted but the correct temp is ready when you want it to be. A compensator is a valve that modulates the boiler flow temp so that when the space is close to its set point less heat is put into the water. This effectively stops overshoot and again reduces energy consumption.
Worcester boilers can all have (I think) an R101 controller fitted and this does what I'm talking about. Couple this with remote head TRVs and you have an eminently controllable and energy efficient domestic heating system.


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## Dibs-h (23 Sep 2011)

YorkshireDave":29g57vse said:


> If it's running costs that are the motivator here, zoning will contribute but putting an optimiser and compensator in will save you even more. An optimiser is a device that looks at what time you wish the house to be at operating temp, looks at inside and outside temps and then calculates exactly when the boiler should start so that no fuel is wasted but the correct temp is ready when you want it to be. A compensator is a valve that modulates the boiler flow temp so that when the space is close to its set point less heat is put into the water. This effectively stops overshoot and again reduces energy consumption.
> Worcester boilers can all have (I think) an R101 controller fitted and this does what I'm talking about. Couple this with remote head TRVs and you have an eminently controllable and energy efficient domestic heating system.



Do you mean weather compensation units? Those I'm familiar with - the modulating valve thingy to prevent overshoot, not heard of that before.

Will be looking at weather compensation when the UFH goes in along with the thermal store.

Cheers

Dibs


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## YorkshireDave (24 Sep 2011)

I think you mean the optimiser - a complex 'sliding' time clock?

Basically its called a compensated flow system. Most systems are designed to operate at (cope with) say -5degs c. At that temp the boiler pumps out a system flow temp of 70degs c (ish). Ones rads are then sized to put sufficient heat into the building to bring to its set point. As teh outside temp warms up (gets closer to the set point) heat is still needed but not quite as much. So, the system calculates what the flow temp should be in order to reach set point and not over shoot (which is where all the wasted energy goes).

Bosch do a great control for about £100 that has an outside air sensor with it. It links directly into the boiler via its networking ability. I have to say its a bit of a sod to get to know but once set correctly its superb. It has an ability to put in offset for the room sensor (that means if your sensor is in the hall and reads 18c when you're toasty in the sitting room at 21c you can put in an 'offset' of 3c effectively fooling the sensor that you've reached set point. It also has night set back so when its really cold the system doesn't switch off just lowers the space temp to say 14c during the night so nowt freezes. It also has an inhibit temp so that if the outside temp is at a point the heating won't come on for no one (thereby stopping the significant other putting the htg on when its a tad chilly in but not out ;-)

All in all a FAB piece of kit that will save a fortune over the years.

D


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## RogerM (24 Sep 2011)

YorkshireDave":1mi1px8v said:


> I think you mean the optimiser - a complex 'sliding' time clock?
> 
> Basically its called a compensated flow system. Most systems are designed to operate at (cope with) say -5degs c. At that temp the boiler pumps out a system flow temp of 70degs c (ish). Ones rads are then sized to put sufficient heat into the building to bring to its set point. As teh outside temp warms up (gets closer to the set point) heat is still needed but not quite as much. So, the system calculates what the flow temp should be in order to reach set point and not over shoot (which is where all the wasted energy goes).
> 
> ...



That's really interesting Dave - thanks for posting. Is there any way the system can differentiate between the zoned radiator circuits and UFH? We are nearly up to roof plate on a large kitchen extension and want to put UFH into it whilst the rest of the house remains on rads. We have concrete floors so retrofit of UFH throughout isn't practical, but is the preferred option for the extension.

Unless I'm mistaken, we will need to keep the kitchen UFH on a separate zone to the already zoned upstairs and downstairs so that lower temp water can go through the UFH when compared to the rads. Introducing a compensated flow system as you describe appeals - but is it practical in the system I've just described?


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## YorkshireDave (24 Sep 2011)

UFH can still operate on a compensated system but it would requirre an addional controll valve and controller. TBA with the effeciency of UFH the additional expense is not really worth it. From a simplistic cost benefit point of view its best to keep it to one type of system. If you have two zones the flow temp should be determined by the highest temp requirement.
David


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## RogerM (24 Sep 2011)

YorkshireDave":2vgnb0wc said:


> UFH can still operate on a compensated system but it would requirre an addional controll valve and controller. TBA with the effeciency of UFH the additional expense is not really worth it. From a simplistic cost benefit point of view its best to keep it to one type of system. If you have two zones the flow temp should be determined by the highest temp requirement.
> David



So are you saying that as the rest of the house is on rads (about 1700 sq ft), the extension (about 400 sq ft) should also be on rads? As the extension is a kitchen/diner/living area we expect to virtually live in it! 

Or that it's fine for the extension to have UFH on a separate zone to the rads, but don't bother with weather compensation?


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## Dibs-h (24 Sep 2011)

YorkshireDave":b7i3j17t said:


> I think you mean the optimiser - a complex 'sliding' time clock?
> 
> Basically its called a compensated flow system. Most systems are designed to operate at (cope with) say -5degs c. At that temp the boiler pumps out a system flow temp of 70degs c (ish). Ones rads are then sized to put sufficient heat into the building to bring to its set point. As teh outside temp warms up (gets closer to the set point) heat is still needed but not quite as much. So, the system calculates what the flow temp should be in order to reach set point and not over shoot (which is where all the wasted energy goes).
> 
> ...



Dave - have you got any links you can post for the Bosch thingy and compensated flow systems in general?

Cheers

Dibs


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## YorkshireDave (24 Sep 2011)

Read this
http://www.greenbuildingforum.co.uk/new ... sionID=189
and this
http://www.worcester-bosch.co.uk/homeow ... controller


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