How NOT to Turn Your Woodburner Into a Bomb

[@Smurphenstein]

My brother worked for an engineering company. They were doing renovations and the plumber stupidly didn't install a safety valve on the hot water cylinder. He had a desk in the office as well as worked in the factory. He went in one Monday after the cylinder was installed over a weekend. His desk area was obliterated and building materials and water were all through the office and parts of the factory. The cylinder had exploded and showered the office with boiling water. They worked 24 hours through the week and had Sundays off although the CNC machines operated all of the time. If it had been installed during the week, someone definitely would have been killed or seriously injured. Stupid thing was they made tapware, valves and the safety valves he should have used so he could have got one for nothing not far from where he was working.

[@davidelliott5843]

A VENTED hot water cylinder makes an excellent thermal store. The same body of water can circulate in gas boiler, radiators and solid fuel burner. The solid fuel has no control valves and may or may not be pumped. The gas boiler has a two port control valve and a pump. The radiators have their own pump and control valve. Hot water is fed by a high performance coil in the top of the cylinder. This keeps tap water away from the circulating water. The body of the cylinder causes the hot water to stratify at the top. It won’t allow mixing between circuits. You don’t need coils to isolate the various circuits.

[@macraghnaill3553]

back in the 1960s we had back boiler behind the kitchen fire to heat the water, I remember that used to boil and my mum asking me to turn the hot tap on and run the water off, whether the tank was vented or not I don't know, temperature was also controlled by opening and closing the damper, if I remember right, closing the damper made the flames go under to boiler so heating the water faster and opening the damper slowed the heating down

[@clivelizwood3916]

Grand video Roger. We have a Dunsley neutraliser on our 2 pipe , wood burner system. This brings in heat from our expensive oil burner and pushes heat into the central heating. Fitted 30 years ago and still working well. It was difficult to find a plumber who understood gravity systems, mostly they seem to rely on pumps. When the power is off, our safety system is to run a hot bath…. Not really a problem on a cold winter evening. Thanks for such a clear explanation of how hot water rises.

[@julianh7853]

Excellent content. Really well explained and enjoyable to watch. Thank you for taking the time to do these videos.

[@SkillBuilder]

Glad you like them!

[@gplusgplus2286]

An open vent is an open wound, and a cause of problems , biggest of which is you have no pressure in the system to operate well. You need 10m of vertical pipe to generate 1bar of pressure. A closed system with proper redundant safety valves a large expansion tank and most importantly a high pressure auto fill valve is the best. The autofill valve and expansion tank are key to replacing cold water quickly when the safety valves open.

[@skf957]

Well said Roger. There are plenty of vids around showing controlled explosions involving unvented HW cylinders. It's the "don't know what you don't know" syndrome with some people, who just plough ahead regardless.

[@SkillBuilder]

They show you that video when you do your G3 trainging but they could equally have shown it with a vented system. They both need care and attention but unvented is actually very safe if it is installed properly and I would rate it as safer. The scenario with a frozen header tank on solid fuel is worse because you have uncontrolled heat. Modern gas boilers have overheat cut-out and modern immersion heaters also cut out rather than boil.

[@rodneythompson3026]

Years ago someone put a header tank above a bedroom, unfortunately it boiled and killed a child, safety is vital.

[@SkillBuilder]

You are right and in the most horrible way imaginable

[@tambias]

There are thousands of feed and expansion tanks over bedrooms in this country. This incident was down to slum landords and poor maintenance.unfortunately a child was killed but was easily prevented if all the proper installation methods were followed.

[@rodneythompson3026]

@@tambias absolutely

[@Clip7heApex]

I was under the impression that the expansion tank needed to be made of metal on boiler stove systems

[@damianbutterworth2434]

I have a wood burner that does the radiators and 2 kilowatts of solar that sends any spare power to the hot water tank so I don`t need gas. Always have hot water. I use an arduino microprocessor and solid state relays to control the pump and valves.

[@d.c7863]

Very good information thank you very much

[@nobbyclarkster]

Roger, you appear to have your jumper on inside out! 😂 All good info though and wasn’t distracted too much. This was quite timely as I have an unused chimney in the kitchen and was seriously considering a wood burning Rayburn or similar and connected to radiator system in addition to the system boiler. I also have a pressurised cylinder so need to rethink this plan.

[@SkillBuilder]

Ha! it would be fairly common for me to walk around all day with my jumper inside out, but it is actually a Snickers thermal base layer with a fleece pilled inner which traps heat against the skin and is super warm. They put that label on the outside. When you look at the front below the zipper you can see their logo.

[@nobbyclarkster]

Looks a decent bit of kit, it’s definitely the time of year to invest in warmer work wear!

[@davek5839]

I installed alot of solid fuel fires with a Thermal store, I found this to be the best system as there is no coil so the fire heats the thermal store up directly. A pump is connected to the the Store which takes heat out and pumps it round the rads and obviously there is some type heat exchanger for the hot water. On many of these systems the home owner also had solar thermal installed which would also heat the thermal store via a coil at the bottom which would provide hot water during the warmer months.

[@MrFlatroofer]

I also have a Thermal store.

[@dwalsh3469]

You are talking about a BLEVE (Boiling Liquid Expanding Vapour Explosion, pronounced ‘bleh vee’). Basically, for a sealed heated water tank, if you keep adding heat, the temperature of the water keeps rising, and because the tank is sealed, the water does not boil. It does get hotter than 100 degrees C though. If the system then breaches, you have super heated liquid water that essentially converts to gas instantaneously. An explosion is just a rapid expansion of gas. A litre of liquid water equates to over a thousand litres of water gas (steam). That conversion creates huge over pressure. It takes about 5psi to knock a house wall down, and a hot water tank BLEVE exceeds that by a good margin.

[@SkillBuilder]

Thank you for that. There was some idiot saying that this was a complete myth and could never happen. I deleted the comment because it might endanger people.

[@beikdw5762]

@@SkillBuilder As per usual, you are right on the money! Best channel on KZbin, I watch you every day!

[@noelburke6224]

The design for dual central heating was engineered by Hugh Maguire in the late seventys during an oil crises. Not over complicated. Most important to have a gravity circuit which is thermosyphone.it has to circulate without the aid of a pump for safety.

[@darrenlucas3435]

Hi Roger great video but i think its a bit behind the time , i have a multi fuel boiler connected to a unvented thermal store it has lots of safety features. Also lot of solid fuel burners are rated to 3bar and state vented or unvented. My thermal store is made by a company called advanced appliances take a look and let me know your thoughts thanks Darren

[@MrFlatroofer]

Same here, had a thermal store for 26 years.

[@tutnallman]

Good detail. I am trying to understand a complex system with legacy pipework and this stuff is most valuable

[@sloughone1]

I Use a plate heat exchanger ( to a closed gas CH circuit)off the open vented circuit (heat store tank)with an injector T pumped return which operates when the tank is at 60C/ room stat /timer. Additional anti boil tank thermostat 90C which is independent of all other controls on the heat exchanger pump.

[@r-joule]

Thanks for the video. Many home owners are now going back in time and heating there houses in a traditional manner to avoid these crazy prices. I really hope you can do a video on how to fit a thermal energy store to a solid fuel stove, there's very little information out there and surely this is the way to go. You can heat the thermal store with solid fuel burner in the evenings and solar panels during the day for heating at night or just hot water in the summer. I really want to fit my own but like I said, there's little information out there on this!

[@stephengreen6338]

Hi Roger, thinking of the potential disasters that are to come, ( and they will), I am now retired from my plumbing trade, I live in the countryside, and so a multi fuel stove from Park ray, been in 20yrs plus. Hot water, and 10rads. My 36 x 18 cylinder just as you described right above the boiler, a pipe thermostat, fitted to just beyond the primary flow expansion, and linked to the pump under the floor pushing the water back through the boiler, 4 tapping's so I cross flowed through the boiler, also took off an heat loss rad, and towel rail off the primary flow and return, works a treat defuse the threat of over spill. I think you should mention if its a low head installation, a metal headed tank should be fitted, and one last thing, you should put emphasis on running a flue liner, and cowl, which as you know if you burn loads of wood it will fire, unless swept, I do mine with a flexy nylon rods, and brush , every year, which is why I have an efficient, and safe system, all the best Roger, always enjoy ya rants

[@SkillBuilder]

Hi Stephen There is more to say on this and I should have mentioned the heat leak radiator and more. I have another video on it soon and we have a video on wood burners and liners.

[@WG1807]

I have such a system, though it's inset in the chimney breast and replaced the old open coal fire. Room heater they are conventionally called. It has a glass fronted door, four tappings from a full wrap around boiler (back and both sides) and runs DHW and seven radiators (now six since I turned off one in a spare bedroom). It's really meant for coal (smokeless) and is excellent when so using, but the price of coal is now prohibitive. When coal was cheaper back in the day (the 90's really), I would have it burning almost constantly for four or five months per year, except for a brief period (a few hours) about once every ten days to give it a good clean out and remove any bits of clinker stuck in the grate. At this rate it would use about 1.5 sacks (75kg) of smokeless coal per week, which at about £8 per sack back then was manageable. The radiators were almost permanently on and the DHW was so hot you could smell it when running. It did often get to the stage where the water began to boil at times and begin rumbling as it vented back into the cold water feed/header tank. I would often run a bath to relieve some of the hot water. Having three young kids at the time was useful - one of them would always want to play about in the bath and of course they were always toasty warm. These days I run it on logs mainly, only in the evenings (nobody home during the day, except perhaps the Christmas period) and sweep it myself twice a year, usually around May or June and again in January. I have hot water more or less throughout (well insulated cylinder), or certainly warm enough for showers (bath is long gone) when I arrive home from work and the fire isn't lit. Good thing about wood fires, burned brightly, is that they heat the water back up to very hot quite quickly and begin to heat the room well within an hour. The radiators will kick in after about an hour as long as I keep the fire fed with logs. The logs are well seasoned, a mixture of species and I usually have the two cords I generally need split and stored by May or June each year. I now have a mental note not to light the fire each year until either Nov 1st or when the indoor temperature falls below 60 degrees F, whichever is soonest. Doubling the loft insulation in 2020 was a good move too, a job I did during lockdown that year. Should have done it years ago.

[@WG1807]

Advantages of coal: Massive energy output. Hours between each fueling period. Constant CH and amazing amounts of scalding hot water. Disadvantages of coal: Cost, especially these days. Having to empty a full ash-pan of hot ashes once per day (quite an art I became good at). Excessive hot water at times. Water so hot it could be dangerous for kids or the unwary. We had no accidents though, the kids were made well aware and soon learned anyway. Advantages of wood: Free more or less if you have a source of logs, except for some chainsaw fuel and oil and a bit of electricity for the splitter. Quick heat as opposed to the slow build up of a coal fire from cold. Very quick hot water. Fire goes out if unattended and overnight, so negating any safety issues with over-pressure or heat. I never attempt an overnight burn, knowing it would be futile anyway and would create lots of smoke and tar. Disadvantages of wood: Having to collect, cut and split logs for about a dozen sessions each spring (keeps you fit though). Having to feed the fire more logs about every 20 - 30 minutes. Cost of logs if you buy them, probably as expensive as coal more or less. You have to have some space for both processing and storing and a fair bit of kit if you want to get your own logs. This would be a chainsaw, an hydraulic splitter, one or two axes, a good pruning saw, a saw trestle and probably a van. You have to know what you're doing too with regard to safety around these tools but that's probably an advantage, as all knowledge is.

[@TheTruffledog]

Super video as always. You, Robin and the crew are so generous in explaining and demonstrating aspects of your trade so clearly. It's very much appreciated. And really entertaining. Would love some info on heat leak rads. I've I've I'm solid fuel Rayburn and I'm always worried that there'll be an unexpected power cut or the circulator pump will give up when it's going full tilt. I know there's an expansion pipe and over-pressure valve, but the gravity flow circuit from the boiler through the coil is very small when stacked against the whole radiator circuit. It's a bungalow though, so not really sure what to do.🤷‍♂️ I'll get a plumber in for opinion but would love to find out more about heat leak / heat sink rads. Very little info online. Thanks again!

[@bambam-cm8we]

I am trying to understand how these systems work, I am a general builder by trade and have reasonable knowledge of plumbing such as hot and cold alterations, adding/change and removing of rads for both combi only and system boilers. My mother in-law has a very old system, this is a parkray coal fire with back boiler and has been this way since or atleast 30 years before I met my better half almost 20 years ago (50 - 70 in total). My partner lost her father due to the big "C" at an early age, the fire is something that he installed prior to his passing. The system in general has not been maintained enough over the years and as you can imagine there were some issues, such as imersion heater didn't work, pump didn't work, some rads had quite literally rusted through and were permanently shut off either side so the rest worked and preventing leaks. Not so long ago a substantial leak did happen and the lounge ceiling collapsed from a burst rad pipe between tank and (from what I can tell) the first rad. Throughout this time I offered multiple times to repair these issues but was prevented by my mother in-law and partner as the fire had to stay lit all year round for hot water. When i mentioned upgrading to a gas boiler and renewal of the pipes, rads etc so that my mother in-law didn't have the burden of adding coal, clearing clinker, ash etc. I met fierce resistance as the cost, disturbance, mess, gas bills (gas has never been connected from the meter outside) and the fact the system was one of the last things my partners father did and is hugely sentimental to all the family. Just prior to Christmas 2022 my mother in-law suffered a stroke and has been in hospital, so I took the opportunity to do the necessary repairs. This is where I struggled with, when seeking advice the concensus was either full replacement or don't touch it at all because of the age and possible things that could go wrong. Nevertheless it had to be done, so I purchased the new parts and prayed 🙏 that nothing would go wrong. I managed to change the imersion heater, pump, move mains stopcock, new electrical bonding, swap 2 rads, replace broken bleed valves on rads, new drain off valves and all went well. When I filled the system up and light the fire, I ran the hot water tap and brown/ black, dirty water was coming from the tap and did so for a good 20 mins. At this point I am thinking that I've somehow split the coil in the indirect tank and would need replacing, my heart sank as I could barely afford what I had spent just on materials and doing the work myself. I drained the system again in preparation for the new cylinder etc and began sourcing the materials and costs and had a list ready for the supplier but something kept niggling in the back of my mind and felt I'm missing something....return the house to have a look over before I order, even though I replaced the ball valve for the loft tank in the past and have been in the loft several times and never noticed that there is only 1 water tank visible. I searched for the 2nd F&E tank but couldn't find it. I spoke to my friend (plumber) and asked him if he could help and his reply was of shock and disbelief that the possibility of a primatic cylinder and full gravity system was still in use.... and I removed the imersion heater so he could see the "bucket" inside. In all the years I've been working I had never even heard of a primatic cylinder and my mate knows of them but has never seen it in the flesh, he described it as "ancient" and "not too far advanced from the roman empire's system, the Hypocaust". This video is a massive help as the family are considering a gas boiler installation but the mother in-law is adamant on keeping the fire and back boiler. I'm looking for some information on the best way to achieve both so I can explain and offer suggestions to the family as even with my limited understanding it is difficult and they have absolutely no construction/ plumbing knowledge at all. If you read this long winded tale (and I hope you do) or someone else does and can provide any information/ advise I would be extremely grateful. Some extra details on the system :- • 28mm pipes from back boiler to tank • 1 pipe system for rads (15mm) • heat leak rad appears to be missing, I think this was removed when the ceiling was replaced through the insurance company due to the leak mentioned above and not noticed until now. • I realise full replacement of pipework, rads, cylinder and additional tank for an indirect tank • 28mm gas supply to boiler location • magnetic cleaner installed to return pipes to boiler • a multi fuel stove with back boiler that can be integrated with a gravity fed system boiler As mentioned I do have some plumbing knowledge, but little to none in solid fuel systems or the integration with gas boilers. My intention is not to do the work as the potential danger of back boiler explosions etc. This is only to try and provide the best possible suggestions to the family both in function and cost. Thank you very much for the video 👍

[@stonefly514]

I think we call that a "Thermo-Syhphon-System"....works very well.

[@toby7077]

thank you so much been looking for a straightforward no heat hero ramble on how this works for months. Not saying heat hero isn't great just hard to understand without these basics! Thank you skill builder

[@SkillBuilder]

You're very welcome!

[@deeeirl]

Great video! I have a 90s Bungalow with Oil CH, Fireplace back boiler and dual coil vented cylinder interconnected that I've been trying to wrap my head around for a while now. Strange thing though is when the Oil CH is running with no fire lit, the primary pipe of the back boiler heats up to the same temperature as the CH. I think a lot of my CH heat is being wasted up the chimney! I wish it was that easy to get a good plumber in these parts!

[@jonnysegway7866]

I think it’s same setup as mine; I can’t fully trace it but I think the Stove is basically another radiator (4 port Stove)

[@richardsandwell2285]

With regard to freezing of the vent pipe and feed creating a blockage, they used to put a antifreeze in central heating systems and then it fell out of favour and people just started putting corrosion inhibitors in which are useless and stopping freezing, maybe building regs need to make antifreeze compulsory, it also helps reduce corrosion and carrys the heat better than just plain water.

[@paula.the.wannabe.hauler]

I think this little drawing is the exact install of my system, only with radiator feeds on it as well. This is gonna really help me out when I need to remove the system to be replaced next month. Cheers as always Roger 👍🙏

[@wallingtonfilming]

Can you do a video on a multifuel burner connected to radiators only not hot water included? Also can you convert an old multifuel burner by adding a back boiler into it and using it on radiators only videos on that would be good as well without using a cylinder for hot water.

[@sweenydeeny5821]

One of the best explained videos on back boilers ,n8ce one

[@paulbarker3588]

Great video Roger, I wish they’d shown your videos when I was doing my construction degree, the explanation from my lecturer mashed my mind; couldn’t figure it out at all back then!!!😂

[@jopjop5533]

My house has waterford Stanley range cooker fired with peat in ireland 14kw boiler we also have a oil boiler on the system too very interesting video.

[@markdavies3842]

Thank you Roger that was so easy to follow Not overcomplicated with Unnecessary waffle Best regards

[@tinytonymaloney7832]

Our building inspector, after I enquired about using out LB for making hot water said that the issue with a pumped system was if you have a power cut when the pump is being called for. We have at least 8 power cuts a year so I'm still hell bent on getting hot water cheap and am looking at using a battery back up via an inverter unit. Like your 2nd sketch our cylinder is not directly above the LB. There is also some gadget you fit under your cylinder called a Dunsley Neutraliser. Not cheap but it allows several appliances to feed your cylinder. Have you ever done a vid on one of these, or maybe can you please?

[@SkillBuilder]

We will be looking at the Dunsley Neutraliser very soon

[@paula.the.wannabe.hauler]

Thanks

[@littlejoeypeakdistrict7546]

Hello As another safety precaution the feed and expansion tank as you say this system has been working for quite a number of years But I myself have used solid fuel in a modern wood boiler stove in a bungalow the cylinder is not in the attic its on the same level as the boiler so once the fire is lit the circulation pump is manually turned on then another two switches one for the rads and one for the hot water cylinder The expansion tank i made out of stainless steel the ball cock was a copper one the over flow pipe from the tank to the outside world was 28mm I did this because hot water coming up into a modern plastic tank with a plastic ball on the valve can deform them with the heat and make them collapse then scalding hot water come through the celling "back in the good days these would have been a big zinc plated tank with a copper ball" Also in the attic as a heat sink in case of power failure was 3 large double rads controlled by powered shut zone valves so if no power they open to give natural rise and fall from the stove Ive just watched you last one with Art McArdel and found it fascinating the set up how you can put it down on paper but when you come to run it its not working as it should so then you start to tweak it ( I wish i had seen him before i started to get information from him would have stopped a lot of head scratching ) But the main thing is Do Not Obstruct The Escape Route For The Hot Water From The Fire And Have A Good Way Of Letting It Escape From The Expansion Tank And in case of a long power cut from the electric board i have a back up generator just to keep the pump running and two 13amp sockets for other needs You do a great job Roger your due a holiday so come up to the Peak District and call in for a brew Regards Joe

[@SkillBuilder]

Ah yes the Peak District, climbing at Stanage as well as cycling. I should come up there

[@robertcole7500]

Fantastic video, very educational. To add another string to the house heating & hot water bow, is it possible to have a wood burner/boiler, in conjunction with an air sourced heat pump. My non-plumbing logic is that the wood burner would only be part of the house heating & hot water for the colder quarter of the year. By the bye, I understood the logic of the hot water tank being directly above , on the first floor. Is it also the case that the 'open tank', in the loft, has to be directly above the hot water tank? Kind regards Robert

[@tribulation138]

I have a oil fed boiler that uses hot water and recirculating pumps to radiators. But I want to tie my wood stove into the system some how to heat the water instead of main boiler in the winter.

[@davidcoombe1811]

yes if it froze it would also freeze the top up tank as well double whammy

[@stevoc4023]

Brilliant Roger, thanks. Could you show how to do it with a closed gas boiler system please? The plumber who done mine just removed the expansion vessel and threw an overflow pipe up to the attic tank. Works ok on the back boiler but the gas boiler now gives problems because the pressure is below 0.5 bar.

[@SkillBuilder]

Ok will do

[@noelburke6224]

You need a hydrolick separator to split the systems. Which combines both pressurised gas or oil and open vent solid Fuels. You can also buy a heat genie will do the same job. These dual and hybrid systems are best installed by heating engineers not plumbers unless the plumber is also a engineer

[@noelburke6224]

A little knowledge and no experience or training is very dangerous these systems should only be installed by competent engineers and professionals and all Installations should comply to health and safety and building regulations. Plus Installations must be certified and insured

[@stevoc4023]

@@noelburke6224 Thanks, yea, the usual. A mate of a mate done it for me. He told me he had done a few before. I didn't get him back because he suggested putting a valve on the overflow, lighting a fire to build pressure, then turn on the boiler and let the fire go out. Noel, could you recommend anyone in Dublin/Kildare? Also, we are building an extension and considering underfloor heating downstairs, can a dual fuel system work with underfloor heating?

[@edfx]

I've seen this setup everywhere: wood/coal burner ~30kW. 3000L accumulation tank. Loader pump group with natural circulation as fail safety. Both furnace and tank have separate safety groups (overpressure valve, automatic air release). Burners have bimetal based air intage regulator, which reduces flame to minimum at 95c. Also some use two-way valve DBV-1 which releases cold tapwater into furnace(cracks cast iron coal burners for sure). Closed system with pressure 1-1.5bar. Which boils at 120c.

[@SkillBuilder]

One of those furnaces blew up in an American school some years ago and killed a couple of people,

[@edfx]

@@SkillBuilder Now I realize why my plumber told that boiler room must have expansion openings, so that it will blow windows out and not raise floor concrete panels off the ground and collapse the whole building.

[@jimcowan6472]

…you’ve reminded me; must call the chimney/flue sweep…log burner time of year again…👍 Another great video Roger. Thanks mate.

[@whitefields5595]

Factory visits. Rog wrote some time ago about you doing SB factory visits. I recently went to Rugby cement works who have regular tours.

[@dah1777]

When I was a kid, many many years ago our hot water tank used to boil everyday in winter when the fire was the only source of heating in the house. And I seem to remember some 15 years ago a couple died when their cold water storage tank got so hot the plastic softened and dumped scolding hot water through the ceiling onto them whilst in bed.

[@SkillBuilder]

You are right that did happen and also a baby was killed in one incident. In theory the plastic float should soften and turn on the cold water

[@whitefields5595]

Roger, excellent vid. I was thinking of installing a back boiler, but my local stove supplier said they were no longer available because they risk cooling the fire down as you describe.

[@dennisphoenix1]

I have a gravity fed cylinder fed from the wood burner back boiler but it's like your second location for the cylinder. It works perfectly including a heat leak radiator in the bathroom for diverting the flow once the water is hot . You didn't mention heat leak radiators ???

[@SkillBuilder]

I neglected to mention the heat leak radiator

[@ianwalker6858]

Next time you do a video make sure you've got your jumper on the right way round. I think you're brilliant and I love you to bits but I couldn't take my eyes off the label sticking out the back of your jumper 😂.

[@SkillBuilder]

Skill Builder 15 hours ago Ha! it would be fairly common for me to walk around all day with my jumper inside out, but it is actually a Snickers thermal base layer with a fleece pilled inner which traps heat against the skin and is super warm. They put that label on the outside for some reason. When you look at the front below the zipper you can see their logo and the zip tag is on the outside. 5

[@ianwalker6858]

@@SkillBuilder I've just been educated! I'm a printer so anything with the label on the outside looks inside out to be me. I should have known with you you'd have a technical reason for wearing it the way you do. That's me told. Keep up the video's though. I think they and you are great! Ian Walker - Stourbridge West Midlands. 😊

[@joesmith822]

Brilliant Roger, appreciate the time you spend putting these videos out.

[@5th_decile]

I'm still on the path of getting more heat out of my iron chimney: it seems possible to me to address the problem of stagnation and tar buildup by just placing a steel pipe of a greater diameter than your original chimney around the latter chimney (in such a way that a hollow cylinder of air is maintained between the two with an opening on the lower end near the stove and the upper end near the ceiling). When the fire is going strongly the chimney heats up and causes a draft in the surrounding annulus in between the inner and outer chimney. When the fire is going weaker this draft subdues and excessive cooling of the inner chimney is averted (If one had attached thermal fins to the chimney in stead, this problem would not have been addressed, or at least less so).

[@prenticedarlington2720]

Excellent video covering the main safely concerns. I also suggest looking at the Laddomat system. A pump and thermostatic valve combination. I seem to remember a video or two clearlyshowing how it works at different stages of the heating cycle, if you're interested.

[@samboth9578]

I use this set up with my thermal store, works great.

[@charliewhite6369]

LoL my cottage has the same system Just moved in. I'm going to get it checked personally i think. Nice video

[@gdfggggg]

Your artistry would be considered shabby chique amongst art connoisseurs. Don’t forget to sign it in the bottom corner.

[@deanthornby2026]

Rocket mass heaters are the way forward ....Roger please have a look into them I'd love to know your thoughts Ok it's not possible for everyone but the money saved on fuel alone makes them worth a look 👍

[@SkillBuilder]

I have seen them and they will be included in a future video

[@fraserstewart7359]

I have built a Rocketmass heater on my Dutch barge. If you need to speak to someone who has built and lives with one let me know

[@deanthornby2026]

@@fraserstewart7359 I'm just about to start building one in my kitchen ... Thanks for the offer if I get stuck I will be in touch 👍

[@fraserstewart7359]

I posted a link to see an image of how mine ended up looking.

[@andrewwilson3663]

Part 3, setting up a common header so the gas or oil boiler can cut in to do some of the heavy lifting when it gets really cold? Anyone for a neutraliser?

[@42RHD]

That was really helpful, Thank You! It consolidated a lot I learned on the City and Guilds which doesn't go into much detail about solid fuel backboilers. And the Blending Valve Bypass is genius!

[@42RHD]

PS. I did worry, and say, that some of that stuff on the other video did have the potential to go BANG, big time, if installed incorrectly! Thanks for the clear up.

[@paulmilner9925]

Thank you so much for this Roger you have educated me with great content

[@myrahouse2368]

Is there a video of battening for Rendering.

[@Arbe1945]

Could you just explain the difference between the two tapping system and the four tapping system. Am I correct thinking the two tapping system is for the hot water. Also how much higher does the main water tank have to be above the boiler copper tank? Do you also have a picture of the blending valve that you use as there are so many.

[@marklloyd9701]

Your jumper is inside out mate 😂😂😂 love the content though 👍🏻

[@SkillBuilder]

It looks like it is inside out but it isn't. It has a fleece on the inside to trap body heat in an air pocket. It is toasty warm. I have cut the label off the back because I got fed up with people telling me. The clue is the zip is on the outside.

[@hazza3651]

does the cylinder have to be vented or can you just have a vent on the flow?

[@mikeywatson7171]

Could use a plate heat exchanger. Keep the solid fuel side vented and the rest of the system sealed. 2 port will protect the unvented. Put a 2 way switch in as well so that when the solid fuel pump is running it breaks the switch live to the gas/oil boiler, then all your existing heating controls don’t need to be altered

[@SkillBuilder]

Thanks Mikey You have summarised the next part of this series. I am still working out what is acceptible in the way of unvented controls. Is one 2 port valve wired through the cylinder stat enough to give full control?

[@mikeywatson7171]

@@SkillBuilder NRV on the return as well maybe? so it can’t reverse circulate

[@oncomingdrizzle]

Northern Irish Council House in the 80s and 90s. Had coal fired central heating from a fire in the living room but hot water tank, which was also the immersion heater, was in the bathroom, almost diagonally across from where the fireplace was downstairs. No pump needed then and heated hot water and radiators? I think these principles seem sound but you also seem to be missing a solution that was in use back then, I've no idea what it was but if I could recreate it, I would jump at the chance.

[@SkillBuilder]

It is gravity circulation. It is covered here

[@oncomingdrizzle]

You can get a fair amount of horizontal travel with the pipes going to and from the hot water tank then.

[@bidders77]

great video as always, fascinating stuff. I would be very interested to see how to safely add a back boiler and therefore the heat generated from my woodburner to my central heating system that currently uses our combi boiler.

[@claudiahamminger-stone3274]

You can add the fb200 flue boiler and connect it directly to your gas central heating for radiators. However you'll need our Wood Safety Kit (from Advance Heating, Kenilworth) and to work out a pump, control system and a safety radiator somewhere upstairs.

[@ZopcsakFeri]

I love this video! Very insightful, thank you! Some propane tank is leaking in the background though if you listen carefully, so better watch out... XD

[@Nightsoil626]

really well explained,thankyou

[@Mc674bo]

Hi Roger grate video , am I right that there has been instances in the past were a conventional system ie gas boiler has exploded the water cylinder because of incorrect installation as in a sealed setup ? . I suppose the key to this is get someone such as your good self in to do the work . I know when pressurised heating system started to first appear they were often referred to as the bomb in your airing cupboard . Thanks for all you do to get people informed and make the right decisions . Best wishes and kind regards as always 😀👍👍👍

[@SkillBuilder]

Hi Michael I have discussed this with a few college instructors in the past. Unvented cylinders, quite rightly, require a certificate to install but the are actually safer than vented cylinders because they have several separate safety devices. I have searched for instances of them exploding and most are not unvented cylinders as we know them or they have been doctored to cause an explosion for training purposes. There are so many in operation these days that I am sure we would know about it if they failed on a regular basis. It is difficult because nobody wants to encourage complacency.

[@Mc674bo]

@@SkillBuilder thanks Roger for the feedback it was probably as much to do with plumbers years ago being suspicious of new technology . Obviously this has been well proven to be not the case because of your findings . As a retired electrical contractor now in my 70th year my memory’s do back a bit , to those early days . Even in my own trade some of the distain directed at the first RCDs by some of the old electricians was quite amazing. Yet of course they must have saved countless lives over the decades . Regards as always 😀👍👍👍

[@sloughone1]

You need a heat leak radiator in the gravity circuit and anti boil thermostat for the circulation pump.

[@SkillBuilder]

You are right, I forgot to put the heat leak rad in but it is on the next instalment

[@maitiu6802]

Hi Roger, where can I buy a blending valve and what does it look like?

[@rymoe6299]

Advance appliances plus wet boiler with 10br rated boiler

[@NICHOLASBYRNE3931]

Thank you Roger that was very informative, one query might not be explaining this correctly, took on board what you were saying about too high speed of pump affecting the draught on the chimney and the heat. So there are some chimneys especially in cold climates which usually are built in the middle of a room, usually kitchen, having a continuous zig zag build of the flu brick which heats the big mass of the chimney breast like a big heat sink, which gives its heat back into the house when the fire is off for example in the middle of the night. Can the conventional water and radiator heating system be used when having this type of chimney. Because of the zig zag like a brick coil in the chimney does if affect the draught needed for the correct operation of the boiler. If it did work wouldn't it really increase the efficiency of the whole heating system, using a wood burner.

[@paulwary]

A large water heater or boiler for men’s showers exploded when I was at work on afternoon shift on the early 1980s. It was like a bomb went off. It took out a double brick wall, and broke every window facing toward it in our building, maybe 50 metres away. The top of the boiler was found to have somehow been launched over our double storey building.

[@SkillBuilder]

Thank you for posting this Paul. Some idiot put a comment on saying that this sort of thing can't happen. I took it down because it is a dangerous comment but it is good to hear from somone who has first hand experience. Hopefully you all escaped unscathed.

[@paulwary]

@@SkillBuilder Miraculously, nobody was injured I believe. Had it happened half an hour earlier at the shift change, there could have been many fatalities. I heard they found a janitor in shock, still holding a hose, in a room near where it went off.

[@S.p.h.2021]

Haha your tops on inside out

[@MrPamurphy09]

You need to have another look 👀

[@eliotmansfield]

Hope his mum wrote his name on the label 😅

[@SkillBuilder]

Ha! it would be fairly common for me to walk around all day with my jumper inside out, but it is actually a Snickers thermal base layer with a fleece pilled inner which traps heat against the skin and is super warm. They put that label on the outside. When you look at the front below the zipper you can see their logo.

[@dreamfpv7865]

Great video , looking forward to the next one 😀

[@kathrynwhitby9799]

that 1st diagram looks exactly like what we had in our cold (sold) council house.

[@stuffoflardohfortheloveof]

That was very interesting and well explained. When I renovated my bungalow (and converted the attic) I desperately needed maximum attic space so we took out the cylinder and tank and my ‘new’ plumber converted our oil boiler to a sealed, pressurised system that, now only runs the heating. Our hot water is a completely separate heat-recovery system. Anyway, we also fitted a new woodburner and, at the time of looking to buy (and prior to meeting my plumber), I researched those with a back boiler and a mains-connected ‘quench system’ (1st time I’d ever heard of them) but could not get any plumber to fit it (each one appeared dead against - frightened even) so we ended up with a standard woodburner. Having then, eventually, got introduced to the new plumber I mentioned it to him and was both surprised and gutted when he said they were great snd that he’d fitted several…….long story short - too late for me but save yourself 😁

[@SkillBuilder]

Art McArdle showed one on the video we did with Heat Hero. I have never come across one but I would like to see one in action.

[@shogun666able]

Not too sure what you're using the connection for on the left of your drawing. if it is a heat leak on its own and running to rads without any controlling rad value fine. If it is a heating circuit connection be aware of what thermostatic rad values will do (if fitted to an existing heating circuit) when they close. Back in the day the lefthand connections your showing would be known as a one pipe system and no rad valves would have been fitted if connected to a solid fuel boiler.

[@ohdfghjkcvbnm2545]

CANT WAIT FOR PART 2 XXXX

[@thomasjohnbirks132]

Excellent.

[@MrFlatroofer]

Good advice. if you don't understand heating. DONT touch it.

[@mikebowen3877]

Hi Roger, im soon going to be doing a boiler stove install on my unvented/pressurised system, i have the correct stove to achieve this. That would make a great video 👍

[@SkillBuilder]

O.k where do you live

[@kevinisaac9139]

Great video Rodger you failed to mention a heat soak rad usually fitted in a bathroom 👍

[@SkillBuilder]

HI kevin I did forget the heat leak radiator but there is a follow up where I mention it

[@adriaan7627]

Not for everyone, because it takes more room, but what about a Rocket Mass Heater? Lots of information here on KZbin about that. The storage of warmth is in stone of clay. It won't heat the entire home, but the fire only has to burn for let's say one or two hours a day, instead of 15 to 20 hours. A saving of around 90% they say comparing a Rocket Mass heater to a regular wood stove. The winning is the flue gas temperature will be 20 to 30 degrees compared to 400 degrees Celsius. Instead of a big mass, it will work for a water boiler? Then add pomp, and you can use it for your central heating system. (Of course take the appropriate safety measures like spoken about in this video made by Skill Builder.

[@julienvailles2986]

I am looking to do this at my place, it will be a dual system (oil currently). In theory it should work and would be brilliant, it takes time to build your knowledge on the subject, it's not so simple.

[@jigsey.]

I just need to convert my unvented system to a vented system...my post on the heat hero created a good debate 😂

[@adrianfielder4675]

Hi Roger, Could you put a copper coil around the top of the flue just above the burner to replace the back boiler? (as I've heard the exit point of the flue from the burner box gets pretty hot. )

[@SkillBuilder]

There are such flue heat recovery devices out there but the fire temperature is variable so taking heat out of the flue causes condensation and tar.

[@loadzofhobbies4219]

You're basically describing a steam engine at the beginning of this video haha.

[@keithdavis938]

Good video. One thing you didn’t include was how does the gravity flow get started when the water is in the same temperature in all the pipes? I’m guessing it’s kicked off because the flow from the boiler is at the top of the boiler, and the return is at the bottom. So inside the boiler, when the fire gets hot, the warmer (less dense) water rises from the bottom to the top, and this is what kicks off the gravity flow to the hot water cylinder. Or does it not work like this?

[@SkillBuilder]

Hi Keith You are right but sometimes you get a battle between flow and return before it settles down. It is quite alarming

[@janm2510]

great so informative. my man!

[@rutgerhoutdijk3547]

Just attach a steam generator and you have both heat and electricity

[@adrianfielder4675]

Hi Roger, me again. I saw a guy who'd put a coil around the flue of his wood burner on a canal boat and he used that to supply heat to his radiators. He never experienced any problems, can you see any issues with it ?

[@SkillBuilder]

Flue heat recovery is an option but if you take too much out the fire won't draw

[@TheTimutube]

Tim again.when I made mine I started with a really big boiler which was home made and suffered with all what you said.I had the boiler in and out quite a few times gradually reducing the size of the boiler to such an extent that all it really was was a baffle above the flames.it worked too well in as much as I incorporated the radiators as well which water would flow into once the hot water was up to temperature through a three way motorised valve.I could switch from hot water to rads independently as required.I put on all the safety valves etc as you mentioned.would I do it again,only if I had too because as I said in previous message my wood consumption literally tripled.loved it though.all that free hot water and heating.I would slumber it at night with both rads and hot water on for safety.it could just about get through the night just.but as you said I had a chimney fire cos of tar build up though that did save me sweeping my chimney lol.I might add that the stove which was all cast started out as a 13 kw so quite big.plus once you incorporate a boiler you really do lose a lot of the stove heat to the room .kindest regards tim

[@SkillBuilder]

Tim it seems as if we lived parallel lives, I did all those kind of things with my mad (Heat Geek) schemes. They are fun but they take over your life

[@TheTimutube]

@@SkillBuilder and ruin lol.my now ex wife was fed up through coming home to find bits of plumbing welding kit all of the lounge and kitchen.loved the learning curve thogh.and still do.every day is a school day lol,hence my being subscribed to your brill channel

[@RosheriMusic]

Another great presentation from you! I have a question from an earlier video, would appreciate some wisdom. When you fit RSJ's into brick work (for loft conversion etc) using a steel plate instead of pad stone, do you lay the plate on a bed of mortar to even out the load and ensure it is level? I have seen a couple of videos where the plate is lying direct on the bricks, surely this can not be good? Appreciate any advice...

[@SkillBuilder]

You can place the steel plate straight onto the brick if the bricks are flat but I would generally put a 3 to 1 bed under the steel plate. I don't think it makes a huge difference it is all about crush resistance.

[@RosheriMusic]

@@SkillBuilder fantastic, thank you...

[@walt42]

with the price of gas going up too, there'll be more houses being blown to bits as people try do it yourself gas fitting in cellars etc, iv'e seen meters and p[pes by-passed and connected with c.clips and rubber tubes, when gas escapes in a confined space and reaches the correct air gas mixture you've got a bomb powerful enough to blow a house to bits if it's ignited by a spark or flame , gas is dangerous if work is not carried out by a skilled gas fitter

[@SkillBuilder]

I agree with that, a bike innertube and Jubilee clips has blown many a building sky high and, you are right, there will be more of them for sure

[@alexanderguesthistorical7842]

Surely, on an open system where the water tank is offset from the boiler, if the pipes that run horizontal are angled slightly (say 1 in 50), both hot and cold feed angled in the same direction, wouldn't that help to keep the heat circulation going in the right direction without needing a pump???

[@SkillBuilder]

Yes that would help and we used to try and do this by taking the flow pipe higher and dropping the return down the wall and under the floor. It will work but it is often very sluggish.

[@noelburke6224]

You are correct it called thermosyphone ,which is a gravity circuit. No valves or pumps can be on this circuit. You pump the radiator circuit only which is controlled by a thermostats on the flow and return. The gravity circuit must have a vent at the heights point of the flow from the boiler. Its call rise to vent

[@arnaudwisman8325]

I have this system but not with a cylinder, i think. But it is open vented. I have 8 rads connected and it works actually quite well. It rarely overheats but if it does the pump switches of and the boiling water pushes up to the water tank on the attic. The sounds are scary :). Anyways that rarely happens. What i do not like about the system is that after a day at work it takes two hours to get the house warm again. Also my shower has yet another electric open vented system. Is there any way i could have a duel system (and connect the shower) where I can set it on a timer and it heats on electricity and when i am home switch to the woodburner? Thanks if anyone has some advise! 😁

[@justinbeveridge3760]

Thanks Roger, another great video. In this video you mentioned a blending valve being installed as a temperature operated bypass. I am having a multi fuel boiler stove being installed and having a ‘Laddomat 21-60’ loading/charging valve fitted on the flow and return next to the boiler stove. My question to you is, will this Laddomat system replace your blending valve bypass or should I have the bypass installed also. Once again thank you & looking forward to your next video.

[@nickdoody4550]

Vacuum

[@gnuthad]

12:30 Why would you put a pump on the hot (feed) side instead of the cold (return) side? My thinking is that having the pump on the hot side requires the pump to operate at a higher temperature than if it was on the cold side and this would lead to a more expensive pump which didn't survive as long. Am I missing something?

[@SkillBuilder]

They are good on either side but the pump on the flow means that it produces positive pressure rather than sucking air in through rad valves

[@gnuthad]

@@SkillBuilder Thanks. That makes sense.

[@philware1546]

Have you got a cylinder steaming off in this video? What's with the hiss? My ears!

[@SkillBuilder]

Sorry about that

[@mikethedigitaldoctorjarvis]

Yes ! you are a fantastic tradesman....but no Bob Ross ! 🤣

[@SkillBuilder]

Maybe it is too late to learn

[@mikethedigitaldoctorjarvis]

@@SkillBuilder It's never too late to learn,every day is a school day.

[@marty259]

The Ads are killing this channel

[@SkillBuilder]

They are the reason we do it. You can pay KZbin for an ad free package but somenone has to pay somewhere down the line

[@effervescence5664]

Hell they boil over on gas, went to a cylinder the other day where the syncro motor had ceased in the on position, boiler going 24/7 in student accommodation. They thought nothing of it, just the water was hot, hot enough to cause the temperature relief to go but it hadn't! Temp reliefs are supposed to be tested once a year on the service but people don't have pressurised cylinders serviced so the seating isn't opened and gets stuck closed. Even if people do have them serviced most engineers won't test them because they hardly ever reseal so you basically have to replace it each year. Had to inform the landlord that normally landlords insurance among other things stipulates it needs servicing annually, something his agent wasn't even aware of. Shove a solid fuel appliance on it and it's a bloody deathtrap, seen it done and RIDDOR'd it. As inefficient as open vented hot water storage is it's a damn site safer and the only way to go with a solid fuel appliance.

[@SkillBuilder]

Yes you are right on all points. The temperature relief valve is a problem. I have known many that won't reseat so it seems they need to be redesigned or made serviceable

[@pigswillbepigs]

Back up, yes you do see the water rise out of a cup a tea, it’s called steam.

[@TurinTuramber]

Wrong. Steam is invisible. Water vapour is condensed steam 🤓

[@pigswillbepigs]

@@TurinTuramber go make a cup of tea,and tell me what that smoke Is coming from it. Fool get back under ya rock