Wood burner draw problem

[dunc78]

Hi There, I am quite enjoying making wood burners. The latest one I am making at the moment seems to have some problems drawing properly.
When I light it up, it gets going well with the door open, but if I shut the door before about 10 mins of full-on burning the fire dies right down, and would probably go out. Once it is up to a hight temp' shuting the door is fine, burns well and no smoke can be seen coming out the flue, just hot air.
You can see the pictures, the air intake is about half way up, I had read that wood likes to have its air come in over the fuel. There is a small baffle plate inside about 50mm lower than the top and only coming just forward of the flue hole. The flue is three and a half inches diameter and I had about 2 meters in hight.
What do you reckon, another air intake, larger bore flue etc?
Cheers,
D
ps. please excuse ugly welds, still getting used to mig

 

[julianthegypsy]

Have you got a good seal at the base of the flue? If not, it will suck air in there instead of pulling it through the damper. The damper looks big enough but I can't see the internal size of course. It may be that the damper isn't opening enough since it runs fine with the door open. Have you let it build up an ash bed? It will run better when there is a solid bed of hot ash, and you are right that wood does need the air on top of it rather than drawing from underneath. Muck about and see what happens.

 

[EngineeringTatty]

My old Hunter Hawk draws air from infront/below the fire. No grate in a wood fire, my thoughts are the air inlet is too high above the seat of the fire.

 

[julianthegypsy]

It is a bit high considering its the only source of air. It's common to have a low one (still not below the fire) and a high one. The high one is normally to feed air into the secondary burn chamber, but you don't have that. That being the case, if the first suggestions don't work, try adding another damper lower down on the door or at the rear. Open that one first then when its hot, try closing that one and opening the side one.

 

[dunc78]

Thanks alot for your advice, I will have a fiddle and let you know the results.
Cheers

 

[pedrobedro]

My old Hunter Hawk draws air from infront/below the fire. No grate in a wood fire, my thoughts are the air inlet is too high above the seat of the fire.

We have a Hunter Hawk 4 which is a multi fuel stove, you can open or close the grate with the riddling lever. Once it's lit we control the fire with the top airwash damper and leave the bottom vent closed as per the instructions. It's a great little stove giving 4.5kw of heat on wood or 3kw on anthracite although we don't often burn coal on it. The design has changed now but Hunter have .pdf on how they work with some nice pictures.

 

[EngineeringTatty]

We have a Hunter Hawk 4 which is a multi fuel stove, you can open or close the grate with the riddling lever. Once it's lit we control the fire with the top airwash damper and leave the bottom vent closed as per the instructions. It's a great little stove giving 4.5kw of heat on wood or 3kw on anthracite although we don't often burn coal on it. The design has changed now but Hunter have .pdf on how they work with some nice pictures.

Mine was the wood only so no grate fitted in the base. Generally left with the bottom vent slightly open and the top damper shut. Only used the top vent during lighting & reviving the fire.

sadly it was left in my last house, now moved and Im without a woodburner..


Plans are afoot....

 

[dunc78]

Just an update on this.
I put another air inlet lower down on the other side. I can now light the fire and close the door without it dying right down. It does still seem to blaze stronger with the door open but once it has been running for about five min's it is hot and burns very well with the door shut. After about 10-15 min's the smoke has pretty much died off out of the flue and it just looks like hot gas coming out. Thanks for the advice. A few pic's: