The Accidental Smallholder Forum
Smallholding => Renewables => Topic started by: Declan on August 15, 2011, 11:54:32 pm
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We have a pumped (unvented) watermains system with oil heating. I would like to change to a wood burner (log type) but have been told that as its a pumped system i cant have it. Something to do with the fact the the wood doesn't know when to stop burning and so it would "boil" the water in the system. As its unvented it would explode. Easier to think of it as its easy to turn off the oil supply when the temperature reaches a certain level- thereby preventing the whole thing getting too hot.
Any suggestions.
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I'm not a plumber or a heating engineer but there's bound to be a way round this ;)
I have a multi fuel stove with back boiler (always worth going for multi, rather than just wood - higher output in terms of Kw) which runs our heating system and hot water, it our previous house we had a gravity run system which also had an oil boiler so we could run the system from oil or the stove.
I think you'll need a header tank for cold (and possibly a hot water cylinder too)
Here's a good site with a forum for asking questions to a registered plumber - he's helped me out in the past http://davidkearns.co.uk/ (http://davidkearns.co.uk/)
HTH
Karen :wave:
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We have a pumped but open system running our central heating (and hot water) from a Wamsler range/boiler.
Legally, you need to have at least one radiator directly attached to the wood burner that is always on (un-pumped) and so can always dump excess heat - we have the towel rail in our upstairs bathroom plumbed in for this job.
The next safety thing, is that the central heating pump comes on automatically once the main water store cylinder reaches a certain temperature ~90 degrees for ours. This obviously won't work in a power outage, so the final safety is a pipe that leads outside the house and can vent steam if the temperature reaches the next point ~95 degrees, I think. The cylinder is then topped up with cold water from the small header tank in the loft if this happens and it brings the temperature down pretty rapidly.
Moving from oil to wood, you're going to want a thermal store (basically a large hot water tank - the bigger the better) anyway and should be able to move to an open system when that is done. (You want the heat store so that you have hot water and heating in the morning without lighting a fire).
I believe you can connect an unvented cylinder to the output of the thermal store, so the wood burner side is vented and the oil-fired side is unvented but I've not looked into that setup much.
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I have oil, solar for water and a Yeoman wood burning stove with a back boiler. The system is gravity fed and goes through a piece of kit called a Dunsley heat exhanger. I have one radiator in the hall that works as a heat leak and a good big header tank. I recently looked at linking up a Wamsler solid fuel stove to the system and was told I would need to have a digital control box to cope with all the variations. My arguement at the time was that I am not daft enough to use the oil fired system at the same time as the solid fuel system but it didn't wash with the engineer who frankly seemed to think I was a bit mad. "I'll just run a bath if it starts banging" didn't impress him. I am now looking at Everhot stove just to provide background heat to my kitchen and do the cooking. It is less of a faff because it plugs into the wall and there is no need to put in a flue, or a solid floor or a digital control box. :)
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We have a 30kw log burning boiler (Bosky) which is on a vented gravity hot water & pumped radiator system. We also have an oil boiler in the return, just before the Bosky. A simple control system of pipe thermostats prevents the oil switching on if the water is already hot, but in extremely cold weather both boilers can work together for a fast warm up. We've never had overheated water - the oil boiler will just switch off once the required temperature has been reached.
95% of the time, we never use the oil boiler (too expensive) but it's useful to have as a back up. The only downside of the plumbing arrangement is that it's very inefficient to heat a hot water tank using just oil this way - the oil boiler has to bring the wood stove up to temperature first, so it acts as a radiator. However, the converse is true - most evenings we light a few logs in the Bosky which is enough to get a tank full of hot water for the next 24 hours, at virtually no cost.
I did assist a friend to plumb in a similar Bosky into a sealed gas system, using a heat exchanger, so I know that can be done too. On their system, a vented solid fuel system has a large water to water heat exchanger which transfers heat into the sealed system, thus reducing their gas consumption when the stove is lit.
We've been running almost totally on wood to heat 14 radiators for over 20 years now, with no problems apart from replacing the first Bosky when it reached about 25 years old (it was second hand when we bought it - the replacement was new).
Right now, we're busy splitting logs for next winter, using a tractor mounted splitter. About 12 tons a year is normal.
Find a sympathetic plumber or heating engineer - a combined system is not too difficult, if well planned.
John
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we run both alongside each other. oil is good for heating the water real quick in the summer. Wood/coal burner can do most of the heating in the winter BUT we have to switch on the pump and the oil for about 10 minutes until the water circulates. Does it make sense? It's not bad. We have it this way because we switched from coal/wood only to oil but wanted to keep the burner....
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I bought one of these from ChimneyHeaters.com . I installed and it works fine. Heats my 2000 square foot house. I have the pump connected to a UPS but I am not sure how long the pump will run if the electric goes out. I had it installed all winter and did not have to turn on my Electric heat once which saved me about 200 euro a month here in Romania.
The Electric is not stable here so I had to rush to take out the fire a couple of times because the water pump had stopped and the pressure valves were going off. The UPS will solve that but I don't know how long a UPS will keep my central pump going. I will attach a pic of what chimney heaters are in case you are not familiar with them. The pump is a Grundfos and has three speeds.
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We were told the same (especially as we are all on one level so couldnt have an upstairs radiator as a heat sink. We finally foung a hetas engineer that would do it and it works fine. He put in an expansion tank in the loft with an overflow pipe that would spurt outside (highly heath robinson, but conforms to regs. In reality in the event of a powercut I now realise we could just run a big bath to dump heat (as well as shutting fire down and removing fuel), so I really dont know what the fuss is about. Hell of a job to find someone to do it though and I'm sure we paid too much but dont regret it. We've kept the LPG connected as back up (against our wishes!!), and in all honesty have enjoyed it for an hour in the mornings through the winter. Good luck!
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I have a multi fuel stove with back boiler (always worth going for multi, rather than just wood - higher output in terms of Kw)
They are generally built better and last longer too.
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I have oil, solar for water and a Yeoman wood burning stove with a back boiler. The system is gravity fed and goes through a piece of kit called a Dunsley heat exhanger. I have one radiator in the hall that works as a heat leak and a good big header tank. I recently looked at linking up a Wamsler solid fuel stove to the system and was told I would need to have a digital control box to cope with all the variations. My arguement at the time was that I am not daft enough to use the oil fired system at the same time as the solid fuel system but it didn't wash with the engineer who frankly seemed to think I was a bit mad. "I'll just run a bath if it starts banging" didn't impress him. I am now looking at Everhot stove just to provide background heat to my kitchen and do the cooking. It is less of a faff because it plugs into the wall and there is no need to put in a flue, or a solid floor or a digital control box. :)
Greetings. Yes the dunsley valve works but it has limitations and can be a pain if it is not set up properly. These valves been superseded with more advanced systems that are much more flexable and allow a number of different connections... Ground source/combi boiler/oil/ multifuel unvented and pressurised systems working together. http://www.h2panel.co.uk/ (http://www.h2panel.co.uk/) the gentleman who has invented these systems is very approachable and has a wealth of experience with hooking different types of systems together.
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Just log burning stobe here - we too have an expansion tank in our loft. It is actually our bedroom but quite large. We have 3 radiators up there in the loft so the expansion tank has to be higher than them. Our log burner has a thermostat that will close a rear air vent if it gets too hot but of course if there is a mass of fuel to burn with the front upfradt ( used to stop soot on glass of stobe) then the fuel will still burn and the water temperature of circulating water will continue to rise.
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Our neighbours have just replaced their oil boiler with a German made wood burner. It takes logs and is unvented. Cost €40,000 with a government subsidy of €3000 to get back when completed. I haven't taken much interest, even as a plumber, as it is an industrial unit really and would never be a heating solution for me. Logs have to be the correct size, that's length and diameter, to suit the feed system. It has two water cylinders and a diverter system, like a modern gas combi-boiler. The expansion vessel is massive! I can see it being a load of complicated trouble! The fuel may be free here, but the servicing and maintenance costs?
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£40K euros???? Blimy Im with you chris ....Bonkers - why would you? limited chance of paypack in your lifetime even with free fuel. I though our system was marginal at £7K!!! Just a note to this thread - our single level system (with miniscule overflow tank in loft) still working well one year on, a serious power cut mid burn will be the test mind you (but I still thing running a bath will be sufficient to deal with the situation.)
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What 40 k for a heating system! My house did not cost much more - and we got a hanger full of seasoned wood left for us.
I wonder how many years I could have electric blankets, towel rails and the gas cooker blasting out heat for if I had 40k to spend. I really must be a peasant to be happy burning a few logs whilst wearing a hat when we have the bitter cold. If I get too cold I go down into the cellar as it is warmer there than in my workshop.
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our 10.5kwatt wood burner is so fierce we can only light tiny fires in it or we bake... and thats fully closed down with the winows open! We probably need to decrease the size of the firebox with firebricks or summat.
I blame all that bloody insulation :innocent:
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hee hee we have a 21.5kw woodburner....:-))) the room isnt huge either (altho the fireplace is and it is also a range cooker and back boiler water heater..)
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ive got 13kw in the living room and 7kw in the kitchen
but no insulation apart from 2ft thick walls. however at least now ive just about finished re-roofing the porch, that bit at least is insulated!
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If it gets too hot...or too cold... you can always move into the porch! :roflanim:
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Insulation - now you are talking. Our log burner runs 9 radiators in a stone built house with 1 meter thick walls. Some of the pipes that feed the radiators leave the house and run through the attached barn before coming back in on the first floor. Our water comes in to the house thru the barn and the pig stye at the other end of the barn. Todays job ( and I keep putting it off) is to insulate the radiator pipes and the cold water pipe that runs at head height along the wall above the chickens and pigs.
We have a mass of insulation in our attic bedroom roof and on it's 3 outside walls but left a feature wall that backs onto the barn. I put in double glazed windows in other rooms but no wall insulation unless I dry line the walls and fill with insulation.
Fire is on now so I will be able to check how well I insulate the radiator pipes - soon >:( .
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If it gets too hot...or too cold... you can always move into the porch! :roflanim:
My parents did say they expected the stove to be roaring and us to be sitting outside in a pool of melted snow :-DDD
We got such a large one as the fireplace is huuuge - a flat arch inglenook type that is nearly the width of the room, so it needed something in proportion....
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Hello,
When last I went to insulating pipes from the boiler room out there in the barn leading into and out of the house, I chose to build an enclosure and stuff it plumb full with wool, a good natural insulation material.(http://i586.photobucket.com/albums/ss304/DonWagstaff/SchafwolleDaemmung_I7659_20101213113558.jpg) A lid on there closes it all up tight too.
Greetings,
Don Wagstaff
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Theres been a lot on renewable forums about sheepwool insulation (even that treated and put in by companies) being infested/consumed by moths. Has yours been in a long time and have you had any mothy problems at all?
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Hello,
It's admittedly been a concern from the beginning, which is why I went so far as to rinse it in a borax solution before going any further. Till now, and that's some two and a half years coming up about this time, I have not had any problems even with my untreated left-overs out there. In fact, it's a funny thing because I was straightening up just today and inspected a gunny sac full of some of that wool I was saving up and everything is aye ok. In one section of the floor insulated with that stuff I even went so far as dumping cedar wood saw dust over the insulation to keep moths out. I don't know even if that was necessary now but it sure smells pleasant with your nose right down there.
Greetings,
Don Wagstaff
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The €40K was only for the boiler replacement. The rest of the system was already there but in a very poor state of repair. They have asked me to sort the problems but in France I need to be licensed to operate. So I'll leave my tools in the UK and carry on with the chicken stuff then!
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Plz excuse if I've mis-interpreted, does this thread provide a solution to the vented / un-vented mating problem?
http://www.accidentalsmallholder.net/forum/index.php?topic=29769.0
:sunshine: :farmer:
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We have just read Chris Mahon's comments on his neighbours heating system. We know his neighbour and his comments are not the truth about the heating system! It is a top quality German boiler and like most wood burners is not the prettiest thing on the planet. That is why it is in a boiler room. The cost was NOT €40,000 but €14,000. It was installed by highly professional tradesman. It is nothing like a combi boiler! As a combi boiler does not have water storage facilities. As a so called plumber he should check his facts. It does not have to have the wood cut to a certain length, width , etc. It hasn't got a feed system, you place the logs in the boiler the normal way, by hand. The expansion vessel is large, as it is a safety device for a large system. The so called complicated servicing is clean the boiler flu and chimney, once a year, as with any other wood burner! It is not rocket science burning wood. He was not asked to repair any of the system, but to install 2 rads. in the existing system. No repair work as there was nothing to repair on the system!