Woodburner CH

D

DeeJayBee123

Joined
12 Jan 2021
Messages
5
Reaction score
0
Country
United Kingdom
Hello :) Am about to install central heating pipework, radiators etc in old part of house in advance of a professionally built house extension which will house a new electric boiler, plus woodburner with back-boiler to provide carbon neutral heating. The attached plan shows a diagram of what I am planning. My questions are whether I am going about this the right way - with a main 'artery' of 22mm o(or 28mm = what's best here?) pipework (in bold) and off-shoots to the various parts of the house. I will be running the 22/28mm pipework in the space between the floors, dropping down via 15mm pipe to the radiators on the ground floor and likewise popping up into the rooms upstairs. Will this provide sufficient circulation - or should I try and close the loop rather than a number of small circuits. Note that I won't be doing an of the work directly from the boiler and wooburner and in the bottom right circuit (as this is all in the new build section) but am keen to save ££'s by getting all the pipework and radiators etc already installed in advance in the old part of the house. I am currently thinking about a woodburner with automatic cooling system to allow a closed (un-vented) system to ensure adequate pressure the heating system. Will also require a pump somewhere in the system - on outward or return...? We are not using the boiler or woodburner for hot water - this is separate and sorted. I have installed central heating from back-boiler woodburner before in an old house, and it worked OK - but more through luck than judgement.
Anyway - all and any advice most welcome - still at early stages...
plumbing design.JPG
 
Last edited:
That has got to be the most complicated sketch ever.
A wood burner on a sealed system is a potential Bomb.
How do you plan linking the boilers and controls.
Pipe size is dependant on load, flow rate and pressure loss.
Pipe work is in parallel not a loop.
 
I have seen some plans
Torrent pipe example.PNG
but always seem to have no sealed systems for wood burners, and when I did some pricing the cost was silly, looking at £20k, I have seen one up and running in bother-in-laws old house, but it was installed as a new build, although diagram shows one tank, actually there were two large tanks, and reinforced floor to take the weight, and the control system was also complex.

The problem with a wood burner is to stop the flue getting tar, and particular emissions the burn rate is very carefully controlled until all wood is charcoal, let it cool and particular emission and tar form, and too hot and heat wasted out of the flue, since it needs an after burn you always have doors on the fire, but the main problem is they can get room too hot.

Using coke or charcoal you have a lot more control, but wood very limited, there have been some condensing systems the rocket and one with motors, but once you use a motor, you need to ensure a power cut or motor failure will not cause a problem, gas and oil is easy, no power and burner turns off, not so easy with solid fuel.

So cooling using thermo syphon is a must, can't rely on some one manually racking out a fire.
 
ericmark said:
I have seen some plans View attachment 218339 but always seem to have no sealed systems for wood burners, and when I did some pricing the cost was silly, looking at £20k, I have seen one up and running in bother-in-laws old house, but it was installed as a new build, although diagram shows one tank, actually there were two large tanks, and reinforced floor to take the weight, and the control system was also complex.

The problem with a wood burner is to stop the flue getting tar, and particular emissions the burn rate is very carefully controlled until all wood is charcoal, let it cool and particular emission and tar form, and too hot and heat wasted out of the flue, since it needs an after burn you always have doors on the fire, but the main problem is they can get room too hot.

Using coke or charcoal you have a lot more control, but wood very limited, there have been some condensing systems the rocket and one with motors, but once you use a motor, you need to ensure a power cut or motor failure will not cause a problem, gas and oil is easy, no power and burner turns off, not so easy with solid fuel.

So cooling using thermo syphon is a must, can't rely on some one manually racking out a fire.
Click to expand...

Your illustration shows a Thermal store with o/v htg.
 
Thanks Terrywookfit. I understood that, usually, woodburners do need open systems - but I was reading about one with an integral cold water supply which prevents it from boiling here https://bit.ly/3i8rLUV and it sounded like a good solution to avoid the need for header tank and open system etc. However - choice is very limited here and perhaps open system might be better but we might not be able to achieve the necessary height as are building in the roof space (house is a bungalow). Anyway - thank you for your comments - all helpful. Learning fast here.
 
Thank you lostinthelight - that link is very helpful.
 
Last edited by a moderator:
Thanks ericmark - helpful comments and thoughts. We are keen to avoid gas and oil due to CO2 and will be using our system sparingly and happy to rake out the fire regularly. Currently in the house with no heating (for the second winter!) apart from a wood burner in one room - and doing Ok.... but looking forward to something that will heat the whole house for sure. Thanks again.
 
Why an electric boiler rather than a heat pump, which would cost much less to run? Some good grants available at the moment, and the RHI rate is very favourable too
 
Just one other question... so if I go for a vented, unpressurized system, will it be OK to lead 15mm pipework DOWN to each ground floor radiator from the 22mm main feed and return that will route in the gap between the floors above? I had thought that perhaps in an unpressurized system, the flow won't be good. Perhaps a simple pump on the hot feed will be adequate to overcome this?
 
If your pipe runs are laid out and sized correctly with a suitable pump, a drop system will work perfectly.! If your FE tank is above the highest rad there should be no problem.
 
You must log in or register to reply here.
Back
Top