Room-sealed wood burning boiler stove

Eoghan Barra

Hi everyone,

Am planning on installing a wood stove in the near-passive self-build I'm working on (roof nearly finished).

I pretty much know exactly what I want, but haven't been able to find anything yet that fits the bill:

1. Wood burning only, not multifuel
2. Truly room sealed, with no combustion air at all from room
3. With back boiler for 2/3 small rads & dhw
4. Moderate total output of about 7-8 kW
5. Freestanding, not inset
6. Preferably (am willing to compromise here) in cast iron and not ultramodern in appearance (anything that doesn't look like a spaceship is a runner)

While there have been a number of useful threads on room-sealed stoves on this forum, none have been in regard to a stove that fits these criteria. Any ideas or suggestions gratefully received.

sas

The following answers are based on what I've been told, I'm no expert.

Eoghan Barra wrote: »

2. Truly room sealed, with no combustion air at all from room

Try also searching for "Closed Combustion System".

Eoghan Barra wrote: »

3. With back boiler for 2/3 small rads & dhw

I've been told that stoves with boilers basically don't exist yet that fulfill 2. i.e. closed combustion system. There are some that are well sealed however but not entirely sealed.

Eoghan Barra wrote: »

6. Preferably (am willing to compromise here) in cast iron and not ultramodern in appearance (anything that doesn't look like a spaceship is a runner)

I would suggest that you are looking for cutting edge technology in a trailing edge design. Imho you can clearly divide stoves into 2 very distinct categories by appearance, those that look that like the majority of what comes out of waterford and those with a more contemporary design.

Cast iron is used where there is a higher temp to deal with i.e. multi fuel stoves. You may struggle to find a timber only stove in cast iron.

It's a big world so you may find what you need but I suspect you'll be compromising on that list.

If you do find a boiler stove that supports closed combustion, please let me know. Not sure I'd like to be paying that bll though.

ootbitb

I have a cast iron Dovre wood burner, I imagine there are plenty of other brands too.

Mine takes air from inside.


http://www.dovre.be/en-be/news/direct-outside-air-supply

Eoghan Barra

Thank for the replies, guys.

ootbitb, unfortunately none of those seem to have boilers, otherwise they're nice stoves.

sas, yes you may well be right in saying that there is something of a contradiction in looking for a stove with cutting edge technology in a less modern style; the problem is that we just don't like the appearance of most of the ultramodern stoves.

Interesting point about cast iron being mostly for multifuel. I have come across a few cast iron room-sealed dedicated wood burning stoves in a plain style - eg saey gustav - but they don't have boilers.

My feeling is that this (ie room sealed/closed combustion stoves) is a rapidly expanding area, and that the various manufacturers are bringing out new models on a very frequent basis. Only a year or so ago there were very few available of any type, now there is a plethora of them, so perhaps in another year we will find what we want (?). :rolleyes:

Will also search under 'closed combustion system'. Thanks again.

ootbitb

could be they think wood isn't up to the job of heating water and space.

in my experience using wood in a range, the cooler boiler surface allows greater condensation of the moisture leading to tar deposits.

TTTT

http://www.lanordica-extraflame.com/en/thermoproducts-wood-thermo-stoves/termonicoletta-d-s-a_p9024

sas

ootbitb wrote: »

could be they think wood isn't up to the job of heating water and space.

I don't think that's the case.

There is no issue finding a wood burning boiler stove, it's the "sealed combustion" feature that is the tricky part.

ootbitb

a technical design problem maybe, from boilerstoves.co.uk......

Air Supply for Combustion in a Log Burning Stoves
A dedicated woodburner will be efficient at burning logs. A stove burning logs requires combustion air to enter the firebox from the top. When the logs heat up they release gases and it is these that create the majority of the heat and flame in the firebox of the stove. If the supply of air only comes from under the logs then the oxygen will often get used up before all these gases are burnt thus wasting heat. A well designed log burning stove therefore introduces a good supply of air above the logs, (often preheated air), to burn off these gases. This increases efficiency and also increases the heat output of the stove.

Eoghan Barra

ootbitb wrote: »

could be they think wood isn't up to the job of heating water and space.

in my experience using wood in a range, the cooler boiler surface allows greater condensation of the moisture leading to tar deposits.

Yes I must admit the reduction in efficiency that a boiler brings to a wood burning stove - as well as the increased tar deposits - is a concern, however I don't want to put in a system based on fossil fuels or electricity for heating water.

I'm actually in quite a quandary about this, but see no practical or cost-effective alternative (that doesn't involve fossil fuels) for the colder months when the solar panel will be less effective.