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    • Scoobnut
    • By Scoobnut 14th Jan 20, 3:17 AM
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    Scoobnut
    Boiler stove nightmare
    • #1
    • 14th Jan 20, 3:17 AM
    Boiler stove nightmare 14th Jan 20 at 3:17 AM
    We have a cosyfire 22 12 kw multifuel boiler stove running 8 rads. But we have so many problems that its driving us nuts and we don't know if it's the stove or us.

    1... It hates coal. We have tried every smokeless coal in the area including, Brazier, Taybright and ecoal50. Put it on the stove it comes up but the stove never gets hot enough to run the heating in fact you can see the thermometer needle falling and after 30 mins the coal starts to die off, turning black.

    2... Getting it to run the heating is a constant battle. We use a mixture up peat and logs but if we don't keep feeding it every 30 minutes it starts to die, we lose heating then have another battle to get it back.
    3.... It was bought on the basis its supposed to have a great overnight burn which the reviews confirm. Not us, no matter what we do or use the stove dies within a couple of hours and if by chance its still warm in the morning then it will take 4 to 5 hours to get the heating to come on.

    4.... Wind is another problem here. We get alot of high winds/gales which cause the stove to loose the ability to run the heating. Once its lost there's no point on running the stove as its then only heating the kitchen.
    We've tried so many ways but nothing works. What are we doing wrong?
Page 1
    • suki1964
    • By suki1964 14th Jan 20, 3:51 AM
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    suki1964
    • #2
    • 14th Jan 20, 3:51 AM
    • #2
    • 14th Jan 20, 3:51 AM
    First of all, are you actually putting in enough fuel to get the stove hot? A lot of new stove users seem to think 4 or 5 pieces of coal is plenty

    Secondly, wind should not be effecting its ability to heat. Yesterday with Storm Brendon giving us gust of 80mph here, trees falling and power outages, it did take a bit longer to get my stove going but once I got a draw I had to shut it down real fast as it was a serious draw and Id have burned a bucket of smokeless in minutes, It got hot though, very hot, very fast

    Have the guys who installed in been around to check the installation ? Have the place you purchased it from come up with any ideas?
    if you lend someone 20 and never see that person again, it was probably worth it
    • A. Badger
    • By A. Badger 14th Jan 20, 8:51 AM
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    A. Badger
    • #3
    • 14th Jan 20, 8:51 AM
    • #3
    • 14th Jan 20, 8:51 AM
    I agree with Suki that under firing could be a potential cause but I also suspect you have a draughting problem - a lack of it. Who installed the stove for you and what sort of chimney arrangement do you have? A 12kw stove needs a lot of air to get it roaring away and it sounds like either not enough air is getting into the stove, or the chimney isn't drawing properly.

    Strong winds really shouldn't make it hard to run your stove - if anything they usually tend to increase the draw on your fire, so that also suggests this is draughting issue.

    If you can't get the original installer back, seek the advice of a good professional sweep.
    Last edited by A. Badger; 14-01-2020 at 7:55 PM. Reason: Corrected US English!
    • Scoobnut
    • By Scoobnut 14th Jan 20, 2:40 PM
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    Scoobnut
    • #4
    • 14th Jan 20, 2:40 PM
    • #4
    • 14th Jan 20, 2:40 PM
    Hi and thank you for your help.

    We moved house in 2017 and the stove was bought to replace a Rayburn that kept setting of the co2 alarm. It was fitted as a homer by one of the men that works for the local stove and heating company that while very reputable are also very pricy. It was fitted with the flue going into the existing chimney with a 904 liner.
    Our previous house used a bucket of coal a day but it wasn't a boiler stove so we expected to add a bit more to this one but a 20k bag or more a day and it still didn't run hot, our coal merchant was asking what we did with it as we were spending 100 a week.

    We have a thermometer on the stove and we try to keep in the optimum range at around 200c and the thermometer on the outtake pipe we try to keep at around 50 to 60 c. The only way to maintain those temperatures is to keep the bottom vent fully open to 3 quarters open. Close it any more and the stove temperature drops quickly. Right now the wind is whistling through the stove and out the bottom vent. We have a cowl but not an antidown draft. We were thinking of getting a rotorvent cowl in the hopes that would help.
    • matelodave
    • By matelodave 14th Jan 20, 4:09 PM
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    • #5
    • 14th Jan 20, 4:09 PM
    • #5
    • 14th Jan 20, 4:09 PM
    Has the stove got any special adjustments or adapters to use with or take out for solid fuel burning. Ours (although not a boiler stove) has a restrictor plate which blanks off most of the grate for burning wood but has to be removed for burning solid fuel.

    You also have to be aware that a lot of the heat that you are generating will be dissipated by the back boiler so it'll probably take a lot more fuel to keep it up to tempt than a bog standard multifuel stove.
    Never under estimate the power of stupid people in large numbers
    • A. Badger
    • By A. Badger 14th Jan 20, 8:50 PM
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    A. Badger
    • #6
    • 14th Jan 20, 8:50 PM
    • #6
    • 14th Jan 20, 8:50 PM
    A 12kw stove being asked to heat a string of radiators will use a lot of fuel. - a bucket a day seems very little to me (I use that in around four hours, just for a 15kw stove alone (no radiators) though it depends on the size of the bucket, of course).

    From what you've added, I'm starting to think the earlier poster who suggested you weren't driving it hard enough was right. Leaving the bottom vents open seems a reasonable way to run a stove running a CH system.

    Your final comment though, saying the wind is whistling through the stove and out of the vent suggests, as I said earlier, that you may have a draughting problem. With a fire burning in the grate, there is only one way the draught should be moving - - up through the firebed and out through the chimney - so I would still suggest you get some professional help, either from the installer or a good sweep.
    • suki1964
    • By suki1964 14th Jan 20, 9:20 PM
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    suki1964
    • #7
    • 14th Jan 20, 9:20 PM
    • #7
    • 14th Jan 20, 9:20 PM
    I think its a mixture of the both

    In work ( well ok my old work but I still socialise there ) the back boiler runs the rads and the hot water for the kitchen and heats the bar and restaurant , 8 rads??? Maybe more and it takes a full tall scuttle of smokless every couple of hours between 9am to 1am. plus logs

    You don't want to know the fuel bill there

    There was a problem with the draught for a long time. Took taking down a tree and extending the flu up out of the chimney before that was sorted


    For me, what I would do, is get the stove hot, and I mean hot that the back bricks are glowing red, then put a layer of anthracite over the top and as soon as you see that glowing red, start closing down. Anthracite takes a lot of heat to get it going but once it takes the heat out of it would put you out of the room. You don't get a flame, just a glow and as long as your back bricks are glowing red, your stove is working. It will take a while to get used to anthracite, I know now exactly what the fire needs to look like before I can layer it up and close down and leave, but that took a lot of trial and error


    Solid fuel is not cheap. its not the cheap option. There was a time there when it was cheaper then oil but not at the moment and its getting dearer with each year. Now whilst I do light my fire every day in the winter, I don't have it on for as long as I used to - oil is cheaper

    As for logs, hiding to nowhere unless you are sourcing for free and have 2 or 3 years storage space. I have to buy in forestry logs and I have to keep them for at least two years. What Im burning now are a tad damp really, I just use one or two to keep the fire going at this time of night till I hit the nest. If I do happen to come across some good dried birch, I save that for the pizza oven as its as rare as hens teeth ( we have very few dicidous trees here )
    if you lend someone 20 and never see that person again, it was probably worth it
    • Scoobnut
    • By Scoobnut 15th Jan 20, 1:49 AM
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    Scoobnut
    • #8
    • 15th Jan 20, 1:49 AM
    • #8
    • 15th Jan 20, 1:49 AM
    We live on in the western Isles so fuel is limited. Our coal yard sells Taybright smokless, while 2 stores sell unknown smokeless all of which can be wet when it comes out the bag. Tesco's sells Brazier and ecoal50 but are already winding down their stock for spring and easter.

    We have been collecting logs which are stored in the garage to season while we buy kiln dried from Tesco as long as they have them. We were buying them from other shops but found them to be wet. There are 2 suppliers that sell builders bags of seasond soft wood for 85 or 90 pound each and no supplier on the mainland will deliver.

    Last year we went through all our peat and had to switch to coal and going through 20k plus a day we couldn't afford on my disability. I was putting coal on it every hour to get it to heat up but it wouldn't. Sadly I am married to a man that never feels cold and while i'm wearing thermals he's in a t-shirt.

    SUKI1964 - My stove has no heat bricks or back boiler. Its boiler is a stainless steal tube that runs along the top near the front of the stove and my husband cleans both chimnies twice a year. We tried ecoal50 which also turned out to be just as usless.

    With a mix of peat and logs and feeding it every 30 mins to an hour we managed to get it hot enough to heat a kettle but not boil. The pipe thermometer went over 60c but most of the time the raidiators stay cold.

    I have been reading up and wonder if the stove is not powerful enough to run them all even with one large one practically off. I originally picked a 16kw but my husband said the 12 would be just as good at half the price. I also read they need balancing and flushing which could explain why only the bottom half remains cold. My husband says the stove is fine and that the raidiators don't need anything done to them.

    MATELODAVE - Our stove is just a plain cast iron stove. The manual says that it should need refuelling every one and a half hours for wood and four for coal but using either and we need to refuel every 30 mins to an hour.

    A. BADGER - Our stove and flue liner are both 18 months old and were cleaned by my husband in the autumn. We have the stove in the kitchen with the open fire on the other side in the living room both have independent chimney pots. We are elevated and very open with the wind blowing down all the chimneys which is cause lighting and burning issues with both the stove and the open fire.

    How often should the raidiators come on? How much should be put on it, I like to fill it as much as possible but my husband says thats too much, that only a half log and some peat is enough. How do we keep it going overnight or when out? Why when we have a hot stove can the water pipe drops below 40c and we can't regain the heating after that.
    Sorry for all the questions but Google didn't have the answers 😁
    • matelodave
    • By matelodave 15th Jan 20, 2:19 PM
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    • #9
    • 15th Jan 20, 2:19 PM
    • #9
    • 15th Jan 20, 2:19 PM
    You could always do some really simple sums. Wood briquettes and well seasoned wood should produce around 4kwh or heat per kg, so to produce 12kwh out of your boiler you'd need to be shoving in nearly 4kg an hour (The Coseyfire 22 stove is only about 75% efficient) I dont know what the heat output of Taybright is but assume that you'd need to be burning between 2-3kg or more an hour to get the maximum output from your stove

    The spec for your stove is around 4-4.5kwh heat from the stove and only 7-8kwh to feed the rads (and possibly the hot water tank). I dont know what sort of house you've got but even my reasonably well insulated bungalow in East Anglia needs around 10-11kw to keep it warm when it's cold outside. So your stove could well be undersized. If you are trying to heat eight rads then you are only getting 1kwh or less out of each of them.

    The stove needs to be hot and if you are sucking all the heat out of it you need to keep feeding it- does it burn better and longer if you reduce the radiator temperatures or turn some of them off so you aren't extracting so much heat

    Ideally the return temp to the boiler should be around 10 degrees less than the flow. Much more and you are feeding too many radiators which cant cope with the heating load.

    Is your heating flow controlled by a pump and thermostat or are you just relying on thermo-syphon to circulate the water.

    TBH the boiler and heating system should be matched to the heat loss of the house rather than what seems like a bit of a guess.
    Last edited by matelodave; 15-01-2020 at 5:09 PM.
    Never under estimate the power of stupid people in large numbers
    • Scoobnut
    • By Scoobnut 15th Jan 20, 11:44 PM
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    Scoobnut
    Hi MATELODAVE,
    After reading your post I went and turned off the livingroom and our bedroom raidiators both off which are the biggest at 2400mm long and 600mm high each. Neither of them worked that we'll as the heat went to the top and nothing after that. Heat wise I have noticed a difference already. We are now running six raidiators and while the stove still needs to be refulled every hour keeping the bottom vent open full keeps it roaring.

    How many kw (roughly) does a raidiator need?
    • matelodave
    • By matelodave 16th Jan 20, 1:46 PM
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    matelodave
    Have a look at this which gives some idea of how a radiator works - look especially at the description of DeltaT. https://www.castrads.com/uk/resources/how-it-works/hydronic-hot-water-radiators/
    Most radiators are spec'd at a DeltaT of 50 degrees (which means that you'll get it's rated output when the temperature difference between the radiator and the outside is 50 degrees (ie rad is 70c and room is 20c).

    Now look at bog standard rads - like Screwfix and you can get an idea of how much heat that different size & configurations will dissipate https://www.screwfix.com/c/heating-plumbing/central-heating-radiators/cat830988.

    Obviously bigger rads dissipate more than small ones. I cant find a 600x2400 but a 600x1800 will dissipate 1850w so I guess a 2400 one will push out nearly 2.5kwh. You only need two like that and there's not much heat left for the rest of them

    Did you have the system flushed when you had the stove installed to get rid of all the accumulated crud in the rads - that will make a difference as will balancing the rads so that the temperature drop across each rad is approx 10degrees. It will also stop one or two rads from using up all the heat.

    Plenty of Youtube videos on bleeding and balancing radiators
    Never under estimate the power of stupid people in large numbers
    • Scoobnut
    • By Scoobnut 16th Jan 20, 11:49 PM
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    Scoobnut
    So it's 24 hours since I shut down the 2 biggest raidiators and the others have got hotter. I have never heard the pump switch on so much, even my son says his room is no longer a freezer. Unfortunately, we have gales again (the norm here in the winter) which has caused the stove to drop in heat, struggle to regain it and have a nice cold wind blowing through the bottom vent so I'm force to shut it down or waste fuel.

    The chimney liner is 18 months old and was cleaned in the summer. My husband as been on the roof and checked the chimney and says its fine, we can't check from the stove side as it fixed through the wall into the chimney. I'm still thinking of getting a Rotorvent Ultralite 2 as it's supoosed to help in high winds and aid draw.

    I worked out (roughly) that we should have got a 25kw stove. 19 to boiler and 6 to room. My husband has agreed to get quotes for flushing and balancing but it does depend on cost. I showed him some YouTube videos but as a retired joiner he's unwilling to attempt it himself.
    • suki1964
    • By suki1964 17th Jan 20, 11:50 AM
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    suki1964
    You need to weigh the cost of getting the job done against cost in savings on the heating over time. If only half the rad is getting hot, there's no point really in throwing coal on the stove at the rate of knots, the rooms are never going to get toasty

    It really does sound like the stove just isn't powerful enough to feed those rads, I have a 5kw stove just for one room - ok its a big room and open plan with the hall stairs opening off it - and that keeps that room at a constant 24oC and takes the chill of the bedroom enough that I have no rad on in there

    I have a weird layout. My stove is actually on my upstairs landing which is ginormous , we use it as a living room and have four rooms leading off it. No hallway because it is actually the landing So two bedrooms are directly off it. The only rad that is on upstairs is the bathroom one

    We did have another stove downstairs but thats been removed because mums not fit to use it now. That was 4kw. 9kw joint and we still had to have the oil running twice a day to heat the rest of the house and the hot water

    Im on the NE coast of Ireland so we have the same weather. Right now theres a solid frost outside still. We do have oil thankfully but we also need an electric rad in mums bedroom on a thermostat for nights as she feels the cold so much. Heating bills are horrendous so it really is beneficial to get what you have got working as efficiently as possible
    Last edited by suki1964; 17-01-2020 at 12:05 PM.
    if you lend someone 20 and never see that person again, it was probably worth it
    • matelodave
    • By matelodave 17th Jan 20, 12:35 PM
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    matelodave
    So it's 24 hours since I shut down the 2 biggest raidiators and the others have got hotter. I have never heard the pump switch on so much, even my son says his room is no longer a freezer. Unfortunately, we have gales again (the norm here in the winter) which has caused the stove to drop in heat, struggle to regain it and have a nice cold wind blowing through the bottom vent so I'm force to shut it down or waste fuel.

    The chimney liner is 18 months old and was cleaned in the summer. My husband as been on the roof and checked the chimney and says its fine, we can't check from the stove side as it fixed through the wall into the chimney. I'm still thinking of getting a Rotorvent Ultralite 2 as it's supoosed to help in high winds and aid draw.

    I worked out (roughly) that we should have got a 25kw stove. 19 to boiler and 6 to room. My husband has agreed to get quotes for flushing and balancing but it does depend on cost. I showed him some YouTube videos but as a retired joiner he's unwilling to attempt it himself.
    Originally posted by Scoobnut
    TBH you should really work out how much heat each room requires (plenty of calculators on t'interweb) to decide what sized rad you need in each room rather than just fitting rads and hoping that they are big enough or just bunging in a boiler with a similar philosophy.

    Have your rads got TRV's - they would help limit the amount of heat that gets dissipated in each room as they'd close down when the room was warm enough and allow the heat to get to other rooms. It's easy to limit the amount of heat a big rad gives out by turning it down but you cant easily get more heat out of a radiator that's too small

    However do ensure that at least one rad (the one in the room with the thermostat) is NOT fitted with a TRV as you need to allow excess heat from the boiler to dissipate.

    Make sure that your room thermostat isn't in the same room as the boiler as it wont operate correctly and will shut down the pump when the room with the boiler gets up to temp rather than when the house does
    Last edited by matelodave; 17-01-2020 at 12:41 PM.
    Never under estimate the power of stupid people in large numbers
    • Scoobnut
    • By Scoobnut 17th Jan 20, 1:44 PM
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    Scoobnut
    The heating was in when we bought the house with all rads were running of a Rayburn. Sadly the Rayburn was beyond repair and we got the stove to replace it. My husband insisted on getting the one we have as it was the cheapest and he said it would be fine. All the raidiators are big, the living and our bedroom are the biggest. I would like to change them as they are decades old and I know that the one in my sons room is far to big but he's not keen on it. Each raidiator has a thermostat except the hall which is the leak raidiator. There is no room thermostat.
    • matelodave
    • By matelodave 17th Jan 20, 2:30 PM
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    matelodave
    If there's no room thermostat what controls the pump - is it just on all the time or has the boiler got a stat to control it.

    As I said you can turn the rads down a bit and balance the system to ensure that just one or two rads don't dissipate all the heat. We had a problem rad which never got hot until we balanced the system and sorted out the TRV's. You could check that they are all working an set correctly
    Never under estimate the power of stupid people in large numbers
    • Scoobnut
    • By Scoobnut 17th Jan 20, 4:43 PM
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    Scoobnut
    We have a pump that's connected to the pipes behind a panel in the bathroom. It comes on when it hits 50c. The thermostats on the raidiators are old and poorly fitted.
    I went online and calculated that we actually need 8.590. The 2 biggest ones are over 3 each and too big for the size of rooms. Replacing the raidiators is the only option.
    • matelodave
    • By matelodave 18th Jan 20, 11:16 AM
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    matelodave
    OK with that bit of info you can probably work out what is happening.

    1 - with all the rads on the pump probably doesn't run very much because the cold return return water is taking a long time to get up to 50.

    2 - With some of the rads turned off the return water will be a bit warmer so the boiler will get to 50 a bit quicker so the pump turns on and off more frequently

    3 - you need to balance the system so the pump runs for a lot longer but you also need to keep feeding the fire to keep the temperature up. In the end if you are extracting all the heat from the boiler so it doesn't get up to 50 degrees the pump wont run at all or only for a very short bursts until the cooler water drops it below 50.

    You might get a better result by just cracking open the radiator valves to keep the pump running - although the rads wont get red hot they should all stay warm for a lot longer. In the end a continuous gentle all round warmth will be better than a red hot blast once every few minutes when the pump kicks in.

    I'm afraid it's going to be a bit of trial and error before you get it right but expect to be showing in at least 3kg of fuel an hour to keep the temperature up. A bigger stove would just use more fuel so see if you can tune your existing system to work a bit better.
    Never under estimate the power of stupid people in large numbers
    • Scoobnut
    • By Scoobnut 18th Jan 20, 12:45 PM
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    Scoobnut
    That makes a lot of sense. I have looked up balancing and yes it looks very faffy but not impossible, somthing I will try. I have noticed the pump switches off after 2 to 3 mins and the return pipe gets hotter quicker than the flow pipe.

    With the livingroom and our bedroom raidiators shut down and the stove running at full throttle it has made a big difference although we have no wind today so it's burning a bit slower. The draft I feel through the bottom vent is normal my hubby says. It would be nice to get the stove to run overnight when really cold but as it never ran the heating It was a waste of fuel.
    • matelodave
    • By matelodave 18th Jan 20, 2:00 PM
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    matelodave
    The flow pipe should get hotter quicker than the return - think about it.

    The boiler makes the water hot, the pump starts up and shoves the hot water out of the flow pipe, through the rads which should dissipate the heat so the return water should be cooler.

    If it's too cold then the boiler will cool down and the pump will stop until it gets hot enough to turn the pump back on and so the cycle continues.

    You need to adjust the flow through the rads so that the return temperature is just above 50 degrees so the pump doesn't keep cycling. You also need to feed in enough fuel to maintain the water temperature above the 50 degree pump threshold if you want to heat the house as well as the room that the boiler is in. Can you divert heat towards the boiler tubes in preference to the room heater.

    However if the pump is not running then the water should get very hot very quickly and can only move away from the boiler in both directions due to expansion or thermo-syphon effects.
    Last edited by matelodave; 18-01-2020 at 2:06 PM.
    Never under estimate the power of stupid people in large numbers
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