Our 29-year old gas boiler became temperamental, and refused to ignite on the odd occasion, so we've just had it replaced. It had a programmer that worked simply on room temperature to decide whether it should run or not, there was nothing clever such as an outside temperature sensor or variable modulation. Our new boiler has only an outside sensor, and bases its decision on whether to switch on, at what modulation, flow temperature etc. on that. So I can set a desired temperature, and I believe that it has some internal algorithms in the control unit (in the form of a heating curve) that makes all the decisions to reach our target temperature. I can't believe that it can be particularly efficient, mainly because it has no internal temperature sensor, but also because it has no idea how efficient our insulation is. The controller can include an inside temperature sensor in its ruminations, but the plumber who fitted it seemed to think that we didn't really need it. As an aside, we do have thermostatic valves on all our radiators.
I'm wondering whether this system is peculiar to the continent (we live in Austria).
Am I missing something, living in the past, or what? Will it really cost less to run, even though it seems to run the heating at a low flow temperature all night?
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A few weeks ago we replaced a traditional programmer with a Nest thermostat.
It looks at the outside(via the Internet) and inside temperatures, and also learns about not only how long your house takes to get warm, but also your comings and goings. Add in the not required but useful ability to control it if required from afar (if you are coming home unexpectedly or something) and it does a jolly fine job of keeping the house warm for us, and having it just at the right temperature as we walk through the door, or get up.
Saving money? Well, sort of. The old system had to be told to come on at a set time, and I then hoped the house would be ready for us. Because the Nest is cleverer, sometimes it comes on earlier than before, costing more. Sometimes later, costing less. But in both cases it's always the right temperature at the right time now, which you couldn't guarantee before. Sometimes it used to be cold, sometimes it had been warm for an hour too long.
The Nest also is clever enough to work out things like your rads will continue to heat the room after the boiler has turned off, for a certain time, so even when on it runs the whole system more efficiently.
Costs a bit, but we had to replace the old programmer anyway.
I don't think it will save a fortune but the place is more comfortable all the time, so worth it for me.
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Your controller sounds more sophisticated than ours.
The new system also came with an aoo to control it, which keeps track of key parameters such as at what power the boiler is running at and the heat of the circulating water. I can also program it with on/off times, shut it off when we're out, turn it on when we come back sooner than expected etc. but it doesn't learn anything. When it's "off", it runs at at an "eco" temperature, which I can set.
It just seems counter-intuitive for it to keep the radiators warm all night when it goes into "eco" mode, albeit at a low level, although I guess perhaps it helps to warm the place up quicker in the morning. The same "eco" setting is used for the periods when we're out during the day.
The old system learnt in a kind of way. You could decide whether you wanted it to switch on (by on, I mean to the comfort temperature of 21 degs) at a certain time, or to have reached that temperature by that time, in which case it came on earlier or later depending on the temperature difference it had to make up.
As you say, perhaps it won't save energy but will keep us comfortable. When it's -10°C outside, which it is as I type, that's important!
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This sounds like the newer idea to control the central heating, so the boiler's startup is based around a variable temperature every 24hrs rather than using time as the variable, this means your boiler is always on but you chose when you want the peaks of temperature, seems that it takes a lot of energy to heat the house from stone cold twice a day so it's more efficient to keep a lower level of background warmth all the time.
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>> This sounds like the newer idea to control the central heating, so the boiler's startup
>> is based around a variable temperature every 24hrs rather than using time as the variable,
>> this means your boiler is always on but you chose when you want the peaks
>> of temperature, seems that it takes a lot of energy to heat the house from
>> stone cold twice a day so it's more efficient to keep a lower level of
>> background warmth all the time.
>>
It's not a particularly big house (165 sq. m.), but it is solid - it has a concrete interfloor between the ground and 1st floor, and all the walls are solid, none of this plasterboard stuff! When we've been on holiday in the winter, it takes around 2-3 days for the place to feel warm again while it absorbs the heat when the heating is switched on again. When we were in the UK for 9 days or so over christmas, we didn't programme the heat to come on before we came home due to the unreliability of the old boiler, and it was chuffing cold for a few days! Once it has warmed up, it retains the heat pretty well, although the roof is not particularly well insulated. There are however problems in improving it due to its construction nature and internal finishing.
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We have a 2011 vintage Vaillant gas boiler, with an outside temperature sensor. But it works with an internal thermostat, and together they decide (I think) how the boiler responds to heat needs via the combined controller and internal room thermostat VRC 430. There is a set of curves shown in the controller manual which are supposed to relate back to the insulation values of the property. Neither our installer nor the Vaillant agent who visited on some minor matter subsequently were knowledgable, (at all), about the control system. However, the controller integrates the internal and external sensors, and sets the flow temperature of the system, as well as the system timer functions, and night time minimum temperature setting, amongst other things. The curve set will depend on the assessment of the insulation etc. Pure guesswork in our case, as neither "engineer" had an inkling.
With a well insulated apartment, apparently the flow curve could be "flat" (0.2 in the range) and at 0C externally the water flow would be about 28C. For a curve of 1.5, the water temperature would be 56C. Selection of the highest curve would produce a flow temperature of 90C. We use a middling curve (1.9) in the range 0.2 to 4.0 in our not very well insulated, UK mishmash bungalow of no particular merit. My impression is that a lower curve, and thus flow temperature would give a more constant "burn" which might lessen overshooting and save energy. However, you might be missing some control gadget or two!
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I thought Hive was a bit gimmicky but I'm coming around to the idea now.
Another plus I hadn't considered was someone mentioned to me that they had it installed in an elderly relatives house so they could turn it up / down / off as required. Also reassuring to know if there was a cold snap they could ensure they were kept warm
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Our installer fiddled with a heating curve of some sort, but I'm not entirely sure he knew what he was doing. I'm struggling to find an English version of the instruction manual for our controller, although I can cope with the German one it would make life easier. Our old boiler was a Vaillant, the new one is a Junkers (part of the Bosch group) which I don't think is common in the UK.
Our house was built in the 70s, and is probably a middling level of insulation in the walls, but could do with more in the roof. As you say, I'm sure this must be incorporated in the heating curve somehow.
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I've watched my sister-in-law come into a room and turn the thermostatic radiator valve fully open, followed by her husband some time later and turn it fully closed.
My daughter would turn her car's climate control to full heat and then turn it down to full cool.
Can these modern controls deal with such behaviour?
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I don't understand how any system can operate efficiently without the programmer knowing the inside temperature. Are all the radiators fitted with thermostatic valves ?
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Modern programmers "learn" how fast a buildig heats up & cools down. You just programme the occupancy times & required temp' But it still needs to know the inside & outside temps to do this.
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>> I don't understand how any system can operate efficiently without the programmer knowing the inside
>> temperature. Are all the radiators fitted with thermostatic valves ?
>>
Yes they are. And I don't understand it either! It seems to me that the system "guesses" based on the heating curve algorithms. I'm a bit concerned that, without an inside temperature sensor, I'm going to be hit with a big bill at the end of the gas accounting year in June.
I do have the option of having an inside sensor fitted later, the controller will quite happily deal with it, so I'll see how it goes when I get the bad news in June.
Last edited by: Mike H on Thu 19 Jan 17 at 10:06
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Can you take meter readings now and compare to last year - might give you an early indication if you are using more / less, although I expect your new boiler will be considerably more efficient anyway
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>> Can you take meter readings now and compare to last year - might give you
>> an early indication if you are using more / less, although I expect your new
>> boiler will be considerably more efficient anyway
>>
I don't have last years reading, the meter is only read once per year, so I have no comparative base.
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>> I do have the option of having an inside sensor fitted later, the controller will
>> quite happily deal with it, so I'll see how it goes when I get the
>> bad news in June.
>>
I'm baffled as to how the system can control the internal temperature accurately without sensing the internal temperature. Sounds like an exercise in technical masturbation / selling more expensive central heating systems.
Last edited by: VxFan on Thu 19 Jan 17 at 16:42
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I agree with spamcan and would add why do it differently as it even if it works it must be less effective? Then again - maybe not...
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>>>I'm baffled as to how the system can control the internal temperature accurately without sensing the internal temperature. <<<<
Surely if the boiler knows the energy input ( from gas control modulated setting) it can calculate the energy being provided to the house. This could also be calculated using the circulation pump flow rate and temperatures - but this may be more difficult to assess).
The rate of loss of heat from the radiators will be a function of system and radiator design and the ambient room temperature. Combine the energy input, flow temperature, the return temperature with outside temperature and the rate of loss of heat to the great outdoors (insulation dependent, ) Hence the internal ie room, temperature could be determined.
Now this is not straight forward basic arithmetic, since the 'constant elements' of 'system design' and 'heat loss (or insulation)' are also functions that are dependendent on temperature differences.
My brain hurts, but I think we are into the realms of differential equations here and a good engineering graduate should come up with the solution shortly. (Not a plumber!)
Add in a learning function on how things change ( wrt time)and a predictive function of ouside temperature vs time of day and there is a Doctorate waiting.
Last edited by: sherlock47 on Thu 19 Jan 17 at 16:58
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What does the outside temperature (i.e. outside the house) have to do with controlling a boiler in the house? The boiler does not know how well insulated the house is. Or whether you have single, double or even triple glaring.
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I had my boiler replaced about twelve years ago. It's quite efficient and the house - detached - is well insulated. However, I find that the thermostat situated in the hall does not control the temperature properly. Is it possible to get a digital thermometer? If that's the correct term. I assume the present thermometer works via a bi-metal strip.
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>> What does the outside temperature (i.e. outside the house) have to do with controlling a
>> boiler in the house? The boiler does not know how well insulated the house is.
>> Or whether you have single, double or even triple glaring.
>>
It has everything to do with how much energy is required to keep the house warm!
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But how good the house is at retaining heat is more important is my point.
Okay the colder it is outside the colder the house could get. But once you get the house to say 20 deg C you can have the boiler switch off. It might still be -4 deg C outside!
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This sounds to me like another classic example of a technology-based solution to a problem that never existed. In all the houses we've lived we've always had an internal room thermostat to control the boiler plus a 24/7 timer on the boiler itself so it can be controlled by day and time preferences as well. In this house, the thermostat is portable so we can move it from room to room if we desire. So if my missus is going to spend a prolonged time in the office, she can take it with her and it communicates with the boiler.
I couldn't give a toss what the temperature outside is. It's the temperature inside that matters.
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>> But how good the house is at retaining heat is more important is my point.
>>
>>
>> Okay the colder it is outside the colder the house could get. But once you
>> get the house to say 20 deg C you can have the boiler switch off.
>> It might still be -4 deg C outside!
>>
But the boiler will know from the history that the house has reached the desired temperature as explained above. Knowing that it is -4 outside allows it to calculate how much energy input is required to keep it at that required internal temperature AND understand by way of prediction what the temperature will (or may) be in say 2 hours time.
Of course this all depends on the system being set up correctly ( ie a plumber who understands the system) and the manufacturers learning and predictive algorithms getting it correct. Most plumbers struggle to set up existing simple systems so perhaps we will become even more dependent on the manufacturers getting it correct. It will follow the automotive industry where the complexity gets to the point where garages and fitters no longer understand the workings. As time goes by the built in systems will get smarter - but I guess that this utopia is still some way ahead.
What we have forgotten is the ability of the end user to 'tamper' so the future will see no radiator valves and 'fines' issued to users who corrupt the software and maintain climate warming temperatures in their own homes. Of course this could be done from smart meters imposing penal rates for inapprpropriate enegy use. A little like modifying ECUs, removing dpfs and fitting non approved spares? Welcome to 1984?
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>>
>> Of course this all depends on the system being set up correctly ( ie a
>> plumber who understands the system) and the manufacturers learning and predictive
>> algorithms getting it correct.
>> Most plumbers struggle to set up existing simple systems so perhaps we will become even
>> more dependent on the manufacturers getting it correct. It will follow the automotive industry where
>> the complexity gets to the point where garages and fitters no longer understand the workings.
>> As time goes by the built in systems will get smarter - but I guess
>> that this utopia is still some way ahead.
>>
Agreed.
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>>
>> Now this is not straight forward basic arithmetic, since the 'constant elements' of 'system design'
>> and 'heat loss (or insulation)' are also functions that are dependendent on temperature differences.
>>
>> My brain hurts, but I think we are into the realms of differential equations here
>> and a good engineering graduate should come up with the solution shortly. (Not a plumber!)
>>
>> Add in a learning function on how things change ( wrt time)and a predictive function
>> of ouside temperature vs time of day and there is a Doctorate waiting.
>>
that sounds feasible, but i'm still failing to see any advantage over just using an internal sense point.
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The outside temperature is taken into account by the nest.
It learns how long your room takes to warm up, and also lose heat, over a few days. That gives it a baseline to work from. They call that "true radiant" if you want to google it.
Then it knows when to turn on the heating to be warm at the time you want.
If it's colder or warmer outside, it then takes that into account, so turns on earlier or later. So supposed to save you money by only being on as necessary.
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As we're talking about heating, as a straw poll, at what temperature do you feel comfortable?
I used to run our living room at 20 - Mrs was always cold. I changed it to 22. She was still always cold. I now set it at 24, and she still sits in her mountain fleece indoors and says she's cold, and we sometimes have to put the electric fire on for her to sit next to. This might be connected with diabetes though (I'm diabetic too but don't feel cold like she does).
Colleague runs his at a hearty 18, but is experimenting with 16. He says his Mrs encourages him to turn it down.
I know everyone is different of course.
So, what temperature do you run yours at?
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21C is generally considered the normal figure for a sitting room with other rooms being cooler.
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>>
>> So, what temperature do you run yours at?
>>
I'd be happy with 20C, SWMBO + Spamette Minor require 22C+, so it runs at 22 morning and evening with a slight step down to 21C during the day.
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>> I'd be happy with 20C, SWMBO + Spamette Minor require 22C+, so it runs at
>> 22 morning and evening with a slight step down to 21C during the day.
>>
Is the house occupied during the day? Ours isn't and I let it fall to a minimum of 14 - it loses about 2 degrees an hour when left to itself.
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>> I used to run our living room at 20 - Mrs was always cold. I
>> changed it to 22. She was still always cold. I now set it at 24,
>> and she still sits in her mountain fleece indoors and says she's cold, and we
>> sometimes have to put the electric fire on for her to sit next to. This
>> might be connected with diabetes though (I'm diabetic too but don't feel cold like she
>> does).
Sounds like my other half - scarf, quilted gilet etc - at 21!
>> So, what temperature do you run yours at?
>>
We ran the old system at 21, but I've set the new one at 22 initially to see how it goes. Remarkably, even though the system has no internal sensor, a thermometer I'm using to track how things are going is reading 22. The outside sensor is show minus 7 as I type this, it was minus 11 at 6pm yesterday :-o
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> This
>> >> might be connected with diabetes though (I'm diabetic too but don't feel cold like
>> she
>> >> does).
>>
>> Sounds like my other half - scarf, quilted gilet etc - at 21!
I think that's quite common, women tend to feel the cold more. I think in all households women always want the heating turned up. I know one house where the heating is so high the husband wears shorts and t shirt indoors all year round.
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>> So, what temperature do you run yours at?
13 degrees as we both like it cool. We will turn it up if we are expecting visitors.
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Yes, ours is always around 16 degrees but we're both used to working outdoors.
That's blown the 'women feel the cold' theory!
Pat
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14° in my East-facing bedroom when I got up at 5:50am. I sleep in my birthday suit, with the window wide open. I like the cold ... as long as I'm under the duvet :)
Got a radiator in the bedroom, it's not been on once in the 6 years we've lived here [I sleep on my own :o)]
Lounge, where I am now, is 20° .. 1° outside. Might have to order some more logs if these 'ere arctic conditions continue.
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> That's blown the 'women feel the cold' theory!
I did say 'quite common', not 'in absolutely every single case on the planet' ;)
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>> Yes, ours is always around 16 degrees but we're both used to working outdoors.
>>
>> That's blown the 'women feel the cold' theory!
>>
>> Pat
>>
OK, 18 degrees here but I work at home and am mainly desk-bound. I turn the heating down/off - husband turns it up/on.
Another one to disprove the theory!
I don't tend to have the heating on during the day except under extreme conditions or if visitors are expected.
Last edited by: hjd on Fri 20 Jan 17 at 19:53
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>> Yes, ours is always around 16 degrees but we're both used to working outdoors.
>>
>> That's blown the 'women feel the cold' theory!
The theory may still hold.
One example against the trend is not statistically valid.
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Actually I'm not convinced that anyone would not feel a little chilly in a room heated to only 16C if they were sitting more or less still for a couple of hours behind a computer screen say dressed in normal indoor clothes. Entirely different if you are moving round a bit. If your job involves a keyboard it starts becoming difficult to type when you are cold.
Also bear in mind that whatever your thermostat is showing your room is unlikely to be at that temperature. A decent thermometer is required to check.
Age also comes into our perception of cold as a visit to a care home will testify
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Tis what ya'll get used to effendi. It's -34° in Yakutsk .. THAT'S cold, knowlmean.
I'm still wearing my shorts & T shirt down here in Sunni Cornwall. Went outside for a mooch at 7am 3°C but didn't feel cold at all at all - no wind see!
But then, when I came back to this Goddam country from Tenerife one August in the previous century, I well-recall sitting on the harbour wall at www.portmellon.net/ while eating fish & chips, and feeling quite cold, being I had become acclimatised to HOT HOT HOT.
When I visit my old neighb next door, she is often sitting in her un-heated stone cottage (until she fires up the wood burner layder on) She's a toughen see, known some hard winters in her farming life, no stranger to HARD work either, which of course, has taken its toll on her body, hence the hip & knee replacement.
Did I ever tell ya about the ice on the inside of my bedroom window when I was a young goat?
:o}
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Of course you get used to the cold to a degree :-) but you will find that offices in Yakutsk and Alaska are heated to the same temperatures as they ar here - around 21C because it is a comfortable working tempeerature if you largely remain immobile and are lightly dressed.. Nobody would actually prefer their office to be 16C unless forced upon them.
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When the first European missionaries were trying to Christianise the heathen Eskimo, they told them all about the fires of Hell. Unfortunately the Eskimo loved the idea and they had to revise the teaching to make Hell unimaginably cold instead. True factoid.
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>>Nobody would actually prefer their office to be 16C unless forced upon them.<<
Apart from those of us who prefer it to be at 16C and have 21C forced upon us.
Thankfully I can work in my office at home and have the window open most days by my side throughout the winter, just to smell the fresh air......something most office workers find unthinkable.
To me, the stale smell of a big heated office is repulsive.
Like Dog, our bedroom window is open all night all year round and over Christmas we were in two hotels with secondary double glazing fixed so the windows couldn't be opened at all.
Neither of us could sleep and we won't be going back again!
Pat
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>> >>Nobody would actually prefer their office to be 16C unless forced upon them.<<
>>
>> Apart from those of us who prefer it to be at 16C and have 21C
>> forced upon us.
The real fun starts when you have two people, one of whom wants 21 and other 16.
We have that scenario. The one who prefers cool of course sits furthest from window. So far they've been amicable but it will only need Mrs 16 degrees to have an off day for fireworks.
Seen it before. Two grown men repeatedly opening and closing a window in turn.
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The ole woman works in an office for 3 days per week. Only 2 peops in the office.
The ole woman likes it cool whereas her colleague likes HEAT. Windows are sealed.
The ole woman uses an electric fan for cool, colleague uses fan-heater for hot = peace!
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Actually very few working environments have the option of opening windows and I don't recall many trucks having the windows open either and I rather suspect that all those truck drivers you see in driving their shirtsleeves have the temperature set at 16C either.
Most people do of course do of course prefer a lower temperature in a bedroom preferably with decent ventilation but if you were to take the temperature actually in a bed under the covers would find it i at least 21C and probably warmer. That is because they would be uncomfortable at a lower temperature and unable to sleep
The plain fact is that the vast majority of people prefer an indoor temperature of around 21C if they are not moving about much and are lightly clad. It is easily verified by observation. The fact that a few people may prefer a lower temperature does not refute that fact.
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18C seems to suit me in the car or the house. If I sit down in the house when it's warmer than that I just fall asleep. Actually, I usually fall asleep anyway if I sit down for more than about 45 minutes. ( except when driving thankfully when I never seem to feel tired until after the journey is over ) Can't count the times I've tried to watch an hour long TV programme and failed to stay awake until the end though. As for feature films, forget it, I'm catching flies before they're half way through. On planes, I can sleep soundly from the moment I sit down and buckle up until the thing wakes me as it hits the destination runway. And yet, if I'm busy, I'll easily miss a nights sleep altogether if that's the way the day evolves.
Never like heat on in bedrooms and always have the window wide open and can't bear my feet covered in bed. Have to leave them hanging out with a bit of a breeze round them.
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That's a good point, i have the temperature set in the car at 17c. Can't really be doing with it much hotter.
While we're talking of temperature, anyone know why shops have the temperature up so high, especially clothes shops, often a horrible hot stuffy feel to many of them.
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>> The plain fact is that the vast majority of people prefer an indoor temperature of
>> around 21C if they are not moving about much and are lightly clad. It is
>> easily verified by observation. The fact that a few people may prefer a lower temperature
>> does not refute that fact.
I like circa 23C or maybe 23.5C, so there!
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Twenny 3 in here now I've got the woodburner a'cooking, feels a bit too warm being we've just come back from a stint with the dogs, so I've opened the door to let some chilled air in ... not for long though!
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>> All is explained.
>>
>> www.isoenergy.co.uk/more-information/weather-compensation-for-heating-controls
>>
I like to see how they substantiate those claims in engineering terms, particularly the up to 15% saving
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"I like to see how they substantiate those claims in engineering terms, particularly the up to 15% saving"
The key words there are, indeed, 'up to'.
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>> Then it knows when to turn on the heating to be warm at the time
>> you want.
>>
>> If it's colder or warmer outside, it then takes that into account, so turns on
>> earlier or later. So supposed to save you money by only being on as necessary.
>>
With no internal sensor, how does it know when the internal temperature has been reached - or is it just estimating based on how much heat delivered?
I can see that with an external plus internal sensor you can play games to push more heat out at lower external temperature to reach the internal set point more promptly, but that's about it.
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>> With no internal sensor, how does it know when the internal temperature has been reached
>> - or is it just estimating based on how much heat delivered?
I was talking about my Nest, spamcan, which certainly does have an internal sensor. Displays it in pretty orange or grey, depending whether the heating is on or off at that moment.
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Ah right, I'll get me coat.
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>> I'm struggling to find an English version of the
>> instruction manual for our controller, although I can cope with the German one it would
>> make life easier. Our old boiler was a Vaillant, the new one is a Junkers
>> (part of the Bosch group) which I don't think is common in the UK.
>>
Is the controller the same as Worcester Bosch Wave? I know they use it in other countries under different names.
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>> Is the controller the same as Worcester Bosch Wave? I know they use it in
>> other countries under different names.
>>
No, just had a quick look. Very different. It's a Junker CW400 that we have, they're part of the Bosch group.
Last edited by: Mike H on Fri 20 Jan 17 at 18:29
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..... but just had a bit of a breakthrough, it looks identical to a Worcester-Bosch Greenstar Sense II Weather Compensation Control, although this one can't be internet-connected, unlike mine. Good call, thank you. Will look into it further.
Last edited by: Mike H on Fri 20 Jan 17 at 18:33
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Thanks BP. I have now downloaded PDFs of the installation and operation manual for the Greenstar controller. It looks pretty much the same as mine in terms of general operation.
Going back to the original post, it seems from the product manual that in our situation it's reasonable to run the system without a room sensor, it made interesting reading. We'll see how it goes.
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A chap asked his wife what she wanted for her Birthday present.
She replied that she wanted something to make her body tremble & nipples stiffen.
So he turned off the Central Heating!
I will get my coat.
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>. Our old boiler was a Vaillant, the new one is a Junkers
> which I don't think is common in the UK.
Not since the Battle Of Britain, actually!
I'll get my coat. :-)
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Central heating controlled by outside temperature - Crankcase
