Lopi Answer with only one secondary tube at the back - Problems

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lope

New Member
May 23, 2016
14
Australia
I have a smoke problem with my brand new Lopi Answer

When I initially load the firebox, and start a top down fire, after the first few minutes that the fire takes to take off, I get a good draft that allows me to have the door fully open and get no smoke out the door. At this point the wood is still catching fire, and the firebox is full and I clearly see lots of smoke burning and moving up the flue. Here I would say the my Lopi Answer is functioning well. Good fire, good draft, no problem. I have a 4 minute video that shows this - where the door is fully opened, there is wood on fire, the draft is established, and there is no smoke flowing out the door.

It is only once the firebox is hotter, that the problem of smoke flowing out the heater begins. Once the firebox is hot, I get smoke regardless of there being wood smouldering or not inside the firebox. If there is smoke in the hot firebox and I open the door, I get a flow of smoke out the door. Very frustrating.

The problem to me is that the Lopi Answer was originally designed in America with several secondary air tubes and for some reason, this design was changed in Australia to only have one secondary air tube at the back.

When the firebox is cold, I can leave the door open and get no smoke being blown out. At this point my guess it that there is no air, or little air, flowing through the secondary air tube.

When the firebox is hotter, my guess is that the flow of air through the single secondary tube starts to flow and this begins pushing whatever smoke there is in the hot fire box out the door.

If I wait until there is no fire, hence no smoke, I can open the door and get no smoke out the door. But as soon as I reload/add one or two logs and begin to get a bit of smoke, this is blown out the door. But here again the firebox is really hot and I am guessing there is lots of hot air flowing through the single secondary air tube.

My guess is that with two or more secondary air tubes, as it is in the original design, the jets of hot air that comes out the tubes, somehow are set in the original American Design, to prevent the above from happening. With only one secondary tube at the back, all the air that would be distributed through the different air tubes now is directed into this single back secondary air tube, and this adds to the pressure with which the air comes out this tube.

Additional, as the holes of the tube are directed straight forward towards the front door, this causes the air/smoke problem that I am getting with my Lopi Answer.

We bought our Lopi Answer brand new from a reputable shop. They have attempted to resolve the problem by installing a higher flue - but we still get the smoke out the Answer.

At this stage I am unsure how to proceed. Our Lopi Answer has only a few weeks of use, with the smoke problem since day one.

Any ideas?
 
It could be the local topography or chimney location is exacerbating poor draft in mild weather. If this were my house I'd get a 1 meter length of cheap, 6" warm air duct for testing. On a calm day, remove the chimney cap and stick the length of pipe, crimp end down, into the chimney pipe. Then try a fire. If that helps then more chimney is needed or an easier breathing stove may be required.

Wood heat has a lot of information on chimneys and how they work.
http://woodheat.org/how-chimneys-work.html
http://woodheat.org/wind-chimney.html

Mild temperature burning. Previous discussions on this installation:
https://www.hearth.com/talk/threads/smoke-problem.155239
https://www.hearth.com/talk/threads/i-can-smell-smoke-but-cant-see-smoke.155365/
 
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