weather compensator or not?

I have not heard that term used for buildings but is quite a good analogy to a tuned circuit.

It is in "simple terms" related to the thermal mass of the building, the radiator output power and the heat loss of the building.

Easier to "learn" than calculate!
Thanks for the "simple" explanation. Now where can I find the "complicated" version? (I never feel that I have really understood something until I have seen the science and maths behind it.) I have done google and wikipedia searches but found nothing really helpful.
 
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Q lol sorry i didnt realise that it generally wasnt a known term :oops: .
Having spent years working with other bms engineers, it is a term bandied around.
Tony is right its the learned rate of heat loss and how long it takes to achieve a set point and allows optimisation and compensation to fairly acurately predict heating ramps and vary according to outside temperature and inside temperature
 
I was interested in the comments earlier in the thread about older houses maybe not suiting weather compensator technology. I have a 1930's bungalow which, even with the usual insulation measures taken, isn't particularly good at retaining heat. It is also oriented North and South with big windows so that one half of the house is naturally a lot warmer than the other. In these circumstances do you reckon that a weather compensator would firstly deliver a satisfactory result at all and secondly provide a saving sufficient to justify the cost over and above that of a standard thermostat?

As a matter of interest roughly how much more expensive is a weather compensator than a thermostat; the websites that I look at seem a little coy on the subject. I should say that I am asking the question in the context of fitting a new boiler so this would not be a matter of retro-fitting.
 
I would expect that an older house is even more condusive to WC because there is little thermal inertia to need to consider. The heat required is pretty much proportional to how cold it is outside!

In the UK, WC is pretty much a boiler design function although there is no reason why if only the boiler makers had remote adjustments of the flow temperature any boiler could use WC. But most dont!

Although it was stated above that WC looks at the indoor and the outdoor temperatures, not all WC does! Many only look at the outside temp.

There are many factors to consider when using WC and setting it up correctly and the siting of the out door sensor is very important.

Tony
 
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Tony,
Thank you for the response. Viessman seem to be the most vocal supporters of the weather compensator concept, at least among the makers that I have investigated, so I guess that they might be the way forward. Rather depressingly I notice that the super duper W.C. that they spend all their time going on about on their web site can't be fitted to their 100 model, which is the only one that is really in my price range. Presumably the "standard" model that can be attached to the 100 range will still do the job.
Best Wishes
Peter
 
I cannot comment on what you have said but the latest 2009 100 model is completely different from the earlier 100 model.

All WC is a good idea if properly used and can save up to about 6% on the gas consumption.

Tony
 
ive been on the viessmann training recently and the new 100 can be used with wc, they had an older model called the dover which was used for their heat only, system and combi boilers and wasnt compatible, the new model is the brussells, the heat only and combi are wc compatible. the system boiler is only compatible if you use the boilers 4 pipe system but im not going into that now. viessmann are the people i have been most impressed with
 
In theory, weather compensation is great. In real life, as soon as the optimum settings are altered, it will negate the small amount of savings possible.

I doubt there are many systems that have it, and actually save more money than it cost to install.

If you want to save money, insulate the most obvious bits in your house, draft proof the worst bits, and you will save at least double of what the compensation dufa will bring you.

If you want to save even more, make sure the trv's are no higher than actually needed, and turn your roomstat down 1 single degree. This exercise alone can easily save you 5% and possibly more. No weather compensation will beat that.
 
Gentlemen,
Thank you very much for your replies. Plenty of food for thought. I think that I will find out how much more the weather compensator will cost than a standard thermostat, assume a rather modest saving on the gas bill and see how the sums add up.
Best Wishes,
Peter
 
Weather Compensation works well as long as the property is uniformly insulated. In other words, it doesn't matter if the insulation is good or bad, it just shouldn't be both in different areas of the same property.

The earlier Viessmann 100 series combi was a car crash, I hope the new 2009 models are better. I know that Viessmann are now trying very hard to repair the damage done and reinstate their reputation.

Both Vaillant and Worcester offer WC alternatives, the Vaillant system has been out for some years now and other than the first few we fitted, they have been reliable, but to be fair, a little complex for the user. The Worcester WC system is new to this country but is an established product from Junkers (another Bosch heating company).
 
Dear Simon,
Thank you for this. I fear that it is the news I didn't want to hear. The insulation in the house is pretty consistent, but its orientation and the large area of window means that the South facing rooms are far warmer than the North facing ones. I suspect that this produces the same effect as differential insulation. Oh well, back to the drawing board.
Best Wishes,
Peter
 
That should be "managed" by the TRVs closing in the rooms with solar heating but leaving the heat to warm up the north facing rooms.

Tony
 
WB now produce the FW weather compensator for the Greenstar 30CDi System boiler, but you also have buy the optional integral diverter valve. It comes complete with outdoor sensor.

All Broag Avanta boilers can be used with weather compensators as well as OpenTherm controls.

The external sensor should be on a north or north-west facing wall, about half way up the wall.
 

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