Friday, February 11, 2011

What Happens When Wood Burns? Article 1 of 3

This is the first of three articles that I will be posting on the above subject.

1. Evaporation of water

2. The emission of smoke To be posted 2/15/11

3. The charcoal phase To be posted 2/18/11

Evaporation of water:
Up to half the weight of a freshly cut log is water. After proper seasoning the water content is reduced to about 20 percent. As the wood is heated in the firebox, this water boils off, consuming heat energy in the process. The wetter the wood, the more heat energy is consumed.

That is why wet firewood hisses and sizzles and is hard to burn, while properly seasoned woo innites and burns easily.

Re-fueling with wet or unseasoned wood in a catalytic stove will send moist smoke to the catalytic combustor and cause the combustor to stop working. It will cause the stove to struggle and not operate properly. In addition re-fueling with wet or unseasoned wood and operating the stove with the by-pass closed, can cause damage to the catalytic combustor.


Ravenvalor said...

When do you bypass the combustor again after a burn? Do you bypass the combustor after the temp drops below 500? When I get up in the morning and the temp is below 500 can I just open the damper (with the combustor still engaged), wait for the temp to rise back above 500, and then reclose the damper down some?

Thank you,

Tim Cork said...

Sorry for the delay in getting you an answer.
After a night's burning, the next morning the firebox temperature will have dropped well below the 500 degrees which is necessary to keep the combustor lit.
All you need to do is open the by-pass (before opening the firebox door)and re-fuel like starting a new fire. Leave the by-pass open for 20 minutes to allow the combustor to come back up to light-off temperature. Remember no smoke is going to the combustor while the by-pass is in the open position. After 20 minutes close the by-pass and the smoke will then travel the the lit combustor.
The combustor needs 500 degrees focused on it for 20 to 30 minutes to cause light-off.
Hope this helps.