Hi from the west midlands

Hi to all, busy building a shed at the moment and slowly gathering materials for my stove project, i will carry on lurking and update you all as and when i get any useful info, currently researching homemade heat exchangers as the new stove if it works, has to replace an open fire with wrap around boiler heating 7 rads and hot water, the boiler was designed with all the info i could gather 15 years ago and even though it has given good service, by today's standards it's really inefficient, regards Les.

Les,

Welcome to the forum.

Hey Les!

les, slight limp wrote:

Hi to all, busy building a shed at the moment and slowly gathering materials for my stove project, i will carry on lurking and update you all as and when i get any useful info, currently researching homemade heat exchangers as the new stove if it works, has to replace an open fire with wrap around boiler heating 7 rads and hot water, the boiler was designed with all the info i could gather 15 years ago and even though it has given good service, by today's standards it's really inefficient, regards Les.

welcome to the forums les

though im curious of your original setup and more so your boiler build

Thanks for the welcome, i couldn't explain the boiler if i tried, i will post a picture and an explanation as soon as i can post pic's, sorry for the second post i didn't think the first one had gone through, just ignore, regards les.

Welcome Les, sounds like that was a pretty large project you put together for heating.
Sure would have been nice to see it.

Glad to have you with us.

The boiler i designed ( pinched various ideas from brochures ) and my friend welded up for me cost 28 pounds for 6mm plate mild steel and the steel pipe fittings to go from the boiler to 28mm copper and looks similar to the inset boiler picture that gadily posted in his old boilers section.
20 years ago it was a great boiler, i had unlimited wood, ( old wooden window frames ) scraping the boiler weekly wasn't a big chore and neither was sweeping the chimney twice a year, i had got hold of a wood burner with a busted boiler to use the doors and frame etc on my existing boiler, one of the door glasses got cracked ( not my kids, they have denied it lol ) and i got a shock when i priced a replacement, so on mooching around the web i came across rocket stoves, rocket mass heaters are not really suitable as my lot are used to central heating, british houses very rarely have a basement so an american style sized unit is out.

My wish list is

Lower running costs
The emissions of a rocket stove, CO2 and water vapour
better efficiency than a rocket stove ( much better reduction )
It must fit into a standard ( British ) fire opening
The boiler / heat exchanger must be as self cleaning as possible, stripping the stove down weekly to clean all the condensates off is a no no.
A vented hot water system for safety.
The stove will be in the house so it must be sealed (no CO leakage )
It must run DHW and 7 rads without running it hard all the time.
A glass panel so my missus can see the pretty flames.
A flue temperature of 50c when on low setting.


There are other things that are just ease of use details, when the weather warms a bit i shall connect some 28mm copper through the window to one of those blue plastic drums ( about the size of a 55 gallon drum ) and see how long it takes to go from cold to 60c and then a test to see how long when the fire is already hot to heat cold water to 60c, i'm happy with the heat output of the old boiler, that will give me benchmark times to either match or exceed, when i start testing i'll post a video on my trials and tribulations, however it turns out it will be a very interesting project for me. Regards les.

It sounds like we are on the same page les.
I want something on the compact scale that can plug right into a chimney and believe it or not I did just that and heated 300 square feet on sticks and I mean sticks.
Looking forward to what you come up with.

Hi Les look forward to seeing what you get up to.

That's a big wish list, but it sounds great. I will be watching this thread closely. Best wishes Les.

Cheers guys, my friend the welder/fitter works at heathyards (google european heathyards ) they make all sorts of stuff for heat extraction, gas pre heaters, power station burners / boilers which are more heat exchangers on a vast scale than what we would traditionally think of as boilers, if you look at the video, the large tube and fin heat exchanger that goes out on the truck at the end, ( they built 5 of those things for 1 job ) should be doable on a smaller scale with 22mm copper pipe and copper strip brazed in between for fitting in the riser box, you would have to have a manifold top and bottom that the heat exchangers would connect to, if you tried to use 1 large exchanger you would just make steam, ( the large ones my friend built were for steam generation ) hopefully i can just keep adding exchangers until i get hot water and not steam, i'm going to build them as panels, pipe comes in from the cold manifold across the exchanger box 180 bend ( i have bought a 180 22mm bender ) across the box again 180 etc to the top of the box and connect to the hot manifold, lots of trial and error but that's where the interest is, i'm thinking something on the scale of ppoty's latest room heater but turned so the fire box and heat exchanger box are next to each other, sort of if you viewed the heater from where the bench is, i'm still building this 4m x 3m shed although a good part will be a separate bike shed, regards les.

Im so interested in this!!! but what video are you referencing? am I missing something?

Try here Toasty...There are a few videos on the channel

aha, thanks Ppotty1!

I'm looking forward to this

Hi toasty, on the site it's called video case studies, it's a corporate video with corporate voice over but there's some good views of different stuff on it, they only show one bay out of 4 on the site, regards les.

Those vids are great.

Im really looking forward to seeing what you create, Les.

Hi again, the council have stopped me building my shed subject to planning approval, my garden is over a hundred feet long but its all on the side and front of the house so i have 2 primary elevations.

I have purchased a 4 channel thermocouple reader and paid an extra tenner and got 2 pipe clamp type thermocouples to go with the 4 standard ones that came with it, my laser infrared thermometer won't seem to read on copper pipes for some strange reason, reads everything else perfectly but not copper.

My boiler burning very damp pallet type wood gets up to 82c in about 2 hours from an almost cold start, the thing hasn't been flushed since it was built and must be full of grot, i say almost cold start because it must reverse convect from the hot tank, no fire for 2 days and the hot and cold boiler pipes were 21c this morning, ambient 15c, the boiler was running at +4-5c up to about 60c and then slowly increased to +9c by the time it got to 80c while reheating a standard (smallish) emersion indirect tank and gravity convecting 3 700 x 500mm double rads, another 10 minutes and the pump kicked in ( 4 downstairs rads ) dropping the boiler temp to 70 and the return to 58, the boiler started to recover pretty quickly so i turned the pump off and let the fire go out.

I seem to get about 3c temperature drop across the rads, any cough cough plumbers out there got any info on this, i'm going to build the heat exchanger and fire box out of thermalite block externally and if any nosy people ask i'll say it's a BBQ regards les.

les you have to run your system at full range to check your system out

my advice drain it and top it up again redrain it 2 more times will give you a clear system of water in it

on running your system if you rads stay warm at sides and top not in middle there clogged with sediment

also your rads might be in series not in parraell

series is one pipe connects to each radiator then to other radiator

the other is where 2 pipes go to one radiator another to another radiator and so forth

Hi gad, the rads got drained and flushed last september, there is a hot pipe that runs the length of the house which feeds all the hot sides of the rads and a return for the cold side, i cocked up when i designed the boiler, the draw on the boiler is pretty impossible to clean properly, i didn't know at the time just how bad the condensate builds up, it's the bottom of the boiler that's probably full of gunk, when first built it could turn the pump on with the tank sensor stat set at 55c in under an hour, now it's nearly 2 hours, normally it does not matter because the fire is never out when it's cold, hopefully this is the last winter for the old boiler, on a lighter note, can you bend normal 22mm pipe 180 or will it need annealing first, cheers les.

yes you can using a spring or a bending machine it also depends on how small you want the 180 copper tube

otherwise this type has to be used

http://www.ebay.co.uk/itm/8mm-10mm-15mm-22mm-copper-end-feed-pipe-tube-fittings-water-plumbing-gas-diy-new-/271528573083?pt=LH_DefaultDomain_3&var=570359772341&hash=item3f385d389b

or 2 90% elbows and piping





your system is the correct one just out of interest would it be the further one with the less drop in heat if so lower your out going valve by a turn on the nearest radiator to the boiler and they should equal out much better on temps as your equaling out your system heating

Thanks gad, i have trouble getting the system balanced as the first rads off are the upstairs and if i balance it right when the pump is on it won't convect very well with no pump, the pump is switched by the tank temp so say on a sunday night when 5 showers come out the pump switches of to give more heat to the tank, i switch the pump of manually before i go to bed and the system is just warm in the morning so it heats up pretty quick with a mixed fire of wood and smokeless coal.

I bought a 22mm 180 tube bender last month to try some bends on some pipe i have spare, i need a vice to put the bender in so i need a shed, the council have stopped me so i will have to rig up a bench outside, all good fun, cheers i'm of to bed, thanks again les.

also remember with convection heating you may have to open the valve more than quoted otherwise your system is at risk of over heating

id try 3/4 on return valve if fine then try 1/2 open on return valve

becomes noisey and rattles like a swine open valve fast as could be boiling in the pipes just as a warning convection works differently to a pumped system

I was advised not to put a control on the tank return for safety, when i first fitted the system i had loads of advice from 2 plumbers / solid fuel heating engineers who ran a plumbing supply place and took it in turns to run the shop while the other was on site, the one guy was really helpful and drew schematics and advised exactly how to do it, we live in the south staffs water area so limescale is a real problem so i flush regularly, the inhibitor stops rusting but nothing for the scale, when i fitted the boiler we welded steel pipes to the boiler so i could get a fitting the other side of the fire place, big mistake, i know now the correct way is to have fittings on the side of the boiler and a separate length of tube to span the brickwork, what i did makes it impossible to get the boiler out without knocking the side of the fireplace out, as they say you live and learn, pretty good job for a plasterer lol, regards les.