Poisoned by carbon monoxide!

[bokehman]

Hi all, new to the forum,

As a kid (30 odd years ago) I was poisoned by carbon monoxide and have never had a fire since.

I have just bought an (broken link removed) double combustion insert and want to know that how the fire is performing is the correct behaviour. The fire is installed in an existing chimney with 5.5 metres of stainless stove pipe.

I fill the fire with wood (3 logs and a load of tinder), probably about 7kilos/15lb total. I open the ashbox door handle quarter of a turn as per the instructions and light the fire. When the thermostat starts the fan I close the ashpan door completely. The fire continues to burn hot (my guess is about 10/12 kilowatts of heat based on what it is replacing).

After about 2 hours the flames go out even though there still appears to be plenty of fuel left to consume. Is this normal? If I open the ashpan door a tad it burns hotter but still no flames. Is this normal? After about 4 or 5 hours of glowing it dies to to nothing.

I've read in other places if the fire doesn't have flames that is is not burning hot enough and may be producing toxic fumes. Is this true?

If there are no flames does that mean double combustion has stopped?

 

[BrotherBart]

I would consider two hours of flames normal for fifteen pounds of hardwood. Curiosity just got the best of me and so I packed my little Jotul F100 completely full of flat, bone dry oak hardwood a few minutes ago and then took it out and weighed it. 15 pounds 4 ounces. With that load stuffed in the little stove I would be quite happy to have flames for two hours. After two hours the fuel you have left is the coal stage of the wood which gives off heat but no flames.

I can't judge by my large stove because I already know that it holds 55 pounds of hardwood.

 

[WILDSOURDOUGH]

Welcome Bokehman,
Although I am not familer with your stove would say that if you are burning dry seasoned wood in a sealed woodstove with a good stovepipe and chimney, that the risk of carbon monoxide poisoning is very minimal.

This is because, if the stove is burning good- then the gases are going up and out. (if it is not burning well or at all, then you will know that right away, like a blockage in the chimney= no fire going up, just smoke comming out all over the place).

Lack of big flames does not mean that the stove is not running properly- hot charcol is still burning and heating the stove. It is a good thing to burn up the wood ( as the writer said above) to charcol stage, and then let that burn down some ( to get the heat out of that charcol, and to conserve wood) before adding more wood.

Best to you.

 

[Gooserider]

It sounds to me like your fire is burning properly. If you do a search on "stages of combustion" you will find where the various stages of burning that a fire goes through are described. However in short when you first start the fire and it gets hot, your wood undergoes a process called PYROLYSIS where it is chemically broken down and the various combustible gasses that are part of the wood are driven out - These gasses are what burns during the secondary combustion part of the fire, and give you all the flames.

When all or most of the gasses have been driven out and burned, what remains is mostly carbon in the form of charcoal, just like you'd use on a barbecue grill. This charcoal will burn with a red glow and put out a considerable amount of heat, but very little in the way of flames. You should let the charcoal burn down most of the way before re-loading.

If you haven't already, you may want to get a thermometer to monitor the temperatures on your stove or stovepipe. You will see the stove burning at a fairly high temperature when you first enter this charcoal burning stage, and it will probably stay about the same or cool very slowly. We usually count the end of the burn-time as being when the stove top drops below about 300 degrees F (I'm guessing about 150 C?) and reload at that time. You should have just enough coals left to let you start a new load of wood going without needing much in the way of kindling.

Hope this helps, if not feel free to ask about what ever you are still having problems with.

Gooserider

 

[babalu87]

I'll echo previous statements and say it seems to be pretty normal from what you described.

Do you have a Carbon Monoxide detector? It is code (rules/regulations) to have one in the same room as a wood stove in the United States.

Good luck with it and stay warm.

 

[thephotohound]

Excellent article on the Stages of Combustion (broken link removed to http://www.montana.edu/wwwpb/pubs/mt8405.html) Simple, but accurate...