I have just joined so please help. We have recently installed solar panels. an oil rayburn which runs central heating/cooking and a multifuel burner, all connected to a thermal store. problems with multifuel burner. we were told this would suply all central heating and water and should not need rayburn. we burn multi fuel burner hard and radiators get hot, but as soon as fire dies down the radiators cool very quickly. cannot live in room if fire burns hard for too long. The only time we achieved radiators hot was when burning household coal which we had left in our bunker, have not managed to achieve this with smokeless, also I thought thermal stores stored hot water and distributed it, but as far as I can see either the fire has to be burning hard all the time or the rayburn is firing up constantly, when either shut down the radiators cool quickly. We have to run the rayburn constantly to get heat to the radiators, which seems to defeat the object of the multifuel burner. we have a rayburn 499k which is lovely, and a woodwarm fireview multifuel 12kw with split saddle boiler. all put in by professionals, we were given no choice but informed this would be fantastic, we find the fire very expensive to run, do not have access to free wood therefore use smokeless fuel, the firebox is very large and will take nearly 10kw in one go. we cannot keep the fire in, and some smokeless does not heat up enough to heat anything. I have heard on forums of smokeless eggs, does anyone know what these are as coal merchant says this is a description not a make. The room size for the multifuel is 22ft x 16ft. we live in a large detached bungalow with 18 radiators. thanks Helen
8 Jan 2010, 1:36 PM
Hi Helen, sorry you are having problems. Can you offer a little more detail please? How large is the thermal store? How much thickness of insulation is on the store? To what extent (thickness) are the walls and roof voids (loft spaces) insulated? When you say the radiators cool quickly, how quickly after the stove goes off do they cool? Its sounds as though your thermal store may be undersized for the heat loss of the building but difficult to say as a number of factors are involved. Smokeless eggs (or 'nuts') may be a reference to phurnacite. I would urge you to consider that there isn't only coal derived fuels or "free wood". That's to say while it is great if you do have access to free wood, burning firewood is better than burning coal. So, if you can't get free wood I suggest you buy in some firewood rather than resorting to coal. You can also get logs made from compressed sawmill waste (pure timber) that burn long, hot and stay in overnnight if your stove will do that. In a sense what you were told was true: the stove is providing your heating but to do that it needs to be burning and probably burning flat out. Besides, stoves need to burn hot to burn more efficiently in general. Had you the idea that it would warm up the radiators and could then be damped down? In a house of that size (while not knowing any detail) this seems unlikely. The heat emitted by the radiators has to be put in by the stove (or Rayburn).
8 Jan 2010, 2:31 PM
Yes, offer more details. How high is the space heating demand and how much of it is coverd ? Is the person who installed the heating system informed about the failure, what is he/she recommending?
9 Jan 2010, 12:00 PM
Hi Julian and heinbloed The thermal store is situated in the loft and has 100mm insulation, the loft is well insulated, and we have cavity wall insulation. the bungalow was originally buiilt late 1950's but with later additions. There is insulation under the roof and fibre insulation on the floor of the loft, however this will make it very cold up there. We were told that the multifuel would suply all our heating and hot water needs, which it obviously does not do, and if it was burning flat out we would need a conveyor belt to keep it going, and a tree that grew money rather than apples! We are at present trying maxibright, which did stay in overnight, but still does not heat rads very well. I have just emptied another coal scuttle into the fire to see if that helps, it is really built up now, hopefully the room will not get too hot We were not told we would have to burn fire flat out constantly when it was installed.
Installer has yet to reply, he did send engineer round before Christmas, he said not to take too many baths and turn some rads off, defeating the object of the excercise really.
the room the heater is situated in is 16ft x 22ft x 8ft. The rads are spread over a large area, not sure of actual size.
rads cool within 30 mins, more or less cold within hour.
tried burning wood, but did not heat anything up. we have also found that fire seems to need constant draught, and is very difficult to light unless bottom ash pit door is left open fully, which apparently we should not do, it should be kept closed at all times, and even the sliding draught should be closed. when we do this the fire goes out.
Just thought I would comment here. Living here in Sweden we get it much colder than in the UK, and it has been cold, further north down to the -40s and between -30 and -40 by daytime. Here in the south about -20 nightime and -10 daytime. My house is one floor open plan when all the doors are open, and they always are, is 86 sq meters, and the same in the basement. I have district heating which at the moment is at about 30C in the rads, just warm to the feel, and on standby downstairs at about 10C just to keep it free from frost. I also have an insert wood burner in the old open fireplace which is brickbuilt, as seen on the picture. I usually light up in the afternoons just for the pleasure of having an open fire, and after about 5 hrs burning birch logs, the whole of the brick surround is like a storage heater, and is warm the morning after. The mornings are never cooler than 18.5C, despite it being -20C ouside. Of course it helps with triple glazing and super insulation, without which I would be stoking the stove nightime as well. For about 5 hrs running the wood burning stove I use perhaps 15 split logs, about 10 kgs total.
9 Jan 2010, 2:30 PM
Sounds apprealing Fridiheim, I wish we had the infrastructure for CHP or district heating here.
Helen, thanks for the details. It would still help to know the size of the thermal store but as it is in your loft I guess it is not a huge one. We have about half the number of radiators that you have. We have a 2000 litre thermal store with 100mm insulation and a 27kw boiler. The boiler runs druing the day at present to keep the store around 70-80 degrees C. That keeps the radiators and hot water going. So you cans see anecdotally just how much energy is needed. Your stove, even at mnaximum, is less than half as powerful and if your store is several hundred litres it will cool rapidly once you stop loading heat into it. We probably burn as many logs as you but during the whole burning cycle i.e. from morning until around 10.00pm. And a stove will not have the same efficiencies as a boiler. I should talk to you installers (who may have given you unreasonable expectations of how the system might perform) and see if they can suggest improvements.
9 Jan 2010, 10:03 PM
@ helendmadell: You have to find out the space heating demand of your building. Get an energy advisor or a heating engineer. They will do the caculation for you and sign for it.
If your heating system simply can't deliver the demand then bring it back to the one who advised you, who sold it to you. If it can deliver what is wanted but doesn't do so the installer made a fault. Then it is his/her turn to rectify the problem. Is your radiator system pumped? What pump? What setting on the pump? How high is the return temperature? Have you checked the manual of your boiler to see how much it will deliver at the water side? Does this match up with the demand? If your boiler delivers only lets say 5 kw but the demand is 20 kW then you'll never get it warm. Each room placed boiler delivers two desired outputs: one for the room, the radiation heat of the boiler. And another for the water circulation, the water side energy. Check the manual, contact the manufacturer for a manual, check the www....
10 Jan 2010, 10:21 AM
Hi everyone,Thanks for replies. We think it is cold here!
Apparently our thermal store is 200 litres.
We have been on to manufaturer of multi fuel heater and have a letter stating that the fire would never run 18 rads so I think we have been misled by installer, which is annoying to say the least as we would have left the central heating to the rayburn and would have installed a much smaller multifuel in the lounge, doing away with knocking half the chimney out etc.and all the pipework which was not cheap. getting on to the installer again tomorrow, no reply to previous letter, getting very angry.
still at least the solar appears to work,so heres hoping for a good summer! Thanks so much for your help. Helen.
10 Jan 2010, 12:08 PM
Good luck Helen. It does look as though you were mislead by exaggerated claims by the installer looking for business. Without wishing at all to sound demeaning, 200 litres is tiny for a system that size (18 emitters) as a thermal store (i.e. a heat bank that would run radiators even with stove off). It sound as if it is simply a buffer - preventing the radiators from taking potentially scalding water directly from the stove. A larger thermal store of one or two thousand litres (imaging a tank almost to the ceiling and 1.2 metres in diameter for the latter example) could be loaded up with heat from the range (Rayburn) overnight as well and topped up by burning a smaller stove during the day. Even so it is a big load (heating requirement) for the equipment you have. Can you have the Rayburn reconnected to the heating system?
11 Jan 2010, 12:45 PM
hi julian. The rayburn is connected to thermal store, so we do have heating, I am just annoyed that we were obviously misled, as I said we would have been quite happy with the rayburn and solar, however we did note that the water from solar cooled down overnight and needed topping up with rayburn for morning shower on occasion, and a woodburner purely for space heating, instead we had our chimney utterly destroyed and a huge multi fuel put in which takes loads of fuel, and if run hot enough for rads is too hot for room, however to run comfortably for room you cannot see the fire as it is so low.Very disallusioned, but we should have checked this out more thoroughly and not taken installers word, although they did come very highly recommended, and the rayburn works really well, and solar is good thanks for help. Helen
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