Definition of a Wood Stove or Heater

Wood heater means an enclosed, wood burning appliance capable of and intended for space heating or domestic water heating that meets all of the following criteria:

An air-to-fuel ratio in the combustion chamber averaging less than 35-to-1 as determined by the test procedure performed at an accredited laboratory, like Omni.

A usable firebox volume of less than 0.57 cubic meters (20 cubic feet);

A minimum burn rate of less than 5 kg/hr (11 lb/hr) as determined by the test procedure prescribed in §60.534 of the U.S. EPA Federal Register and performed at an accredited laboratory;

A maximum weight of 800 kg (1,760 lb). In determining the weight of an appliance for these purposes, fixtures and devices that are normally sold separately, such as flue pipe, chimney and masonry components that are not an integral part of the appliance or heat distribution ducting, shall not be included.

When Wood Burns Part 3 of 3 Articles

This is the third of three articles posted on the above subject.

1. Evaporation of water. Posted 3/20/09
2. The emission of smoke. Posted 3/24/09
3. The charcoal phase.

The charcoal phase:

As the fire progresses and most of the gases and tars have vaporized out of the wood, charcoal remains.
Charcoal is almost 100% carbon and burns with a red glow and very little flame or smoke. Charcoal is a good fuel that burns easily and cleanly when enough oxygen is present.

When Wood Burns Part 2 of 3 Articles

This is the second of three articles on the above subject.
1. Evaporation of water. Posted 3/20/09
2. The emission of smoke.
3. The charcoal phase. To be posted 3/27/09

The emission of smoke:
As the wood heats up above the boiling point of water, it starts to smoke. The smoke is visible result of the decomposition of the solid wood as it vaporizes into a cloud of combustible gases and tar droplets.
The smoke will burn if the temperature is high enough and oxygen is present. When the smoke burns, it produces the bright red flames that are characteristic of wood combustion.
If smoke does not burn in the firebox, it will exit the appliance and into the chimney where it will either condense forming creosote deposits or be expelled as air pollution.
Unburned smoke represents an efficiency loss because it contains a large part of the total energy in the wood. However, catalytic stoves with the use of a catalytic combustor, burns this smoke before it is expelled as air pollution and burns it as a fuel to produce heat that can be 2-3 times hotter than the firebox temperature.
This also gives a higher efficiency out of the stove. At the same time, the catalytic combustor will burn up to 90% of the creosote contained in the smoke.
(Read more about this in earlier articles I have posted)

When Wood Burns Part 1 of 3 Articles

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 3/24/09
3. The charcoal phase To be posted 3/27/09

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.

Tips on What Type Wood to Burn

Hardwoods or Softwoods?

Softwoods like fir, spruce, and pine are less expensive than hardwoods. Softwoods are easier to ignite and burn rapidly with a hot flame.
If you want a quick-warming fire that will burn quickly, softwoods are your best choice.

However, if you’re a serious wood burner using a catalytic wood burning stove, hardwoods are the best choice.
Hardwoods such as oak and birch provide a longer-lasting fire with a shorter flame.

A mixture of softwoods and hardwoods can be used for easy starts and long lasting burns.
All woods should be season dried before burning in order to provide the cheapest, cleanest, and safest fire.

Note: Never burn rubbish, chemically treated wood such as discarded railroad ties, utility poles, and old yard fences. All emit poisonous fumes and could add to those materials that collect in the chimney, increasing the possibility of a chimney fire.

Note: Never burn coal in your catalytic stove. Never burn artificial or manufactured logs, which are composites of sawdust, chips, colorful chemicals, starch binders, and wax. They might do harm to the catalytic combustor.
“Burn only season dried wood”

Loading Firewood in the Firebox

How to load your fuel

Techniques may vary, but shown are the two most common.



Small pieces of wood arranged loosely in a crisscross pattern burn quickly because the combustion air can reach all the pieces at once.











Larger pieces placed compactly burn more slowly because there are fewer spaces where the air can penetrate the load.











Never add just one or two pieces of wood to a fire. Three or more pieces are needed to form a sheltered pocket of glowing coals that reflect heat toward each other and sustain the fire.

HPB EXPO 2009

I will be at the HPB Expo 2009 at the Reno-Sparks Convention Center in Reno, Nevada from 3-17-09 through 3-21-09. I will also be conducting a training class on wood stove catalytic combustors.

If you plan to visit the expo, please stop by Applied Ceramic's booth and say hello.

The Exhibit hours are:
Thursday, March 19, 2009
9:00am - 5:00pm
Friday, March 20, 2009
9:00am - 5:00pm I will be conducting a class at 1:00 pm Room TBD
Saturday, March 21, 2009
9:00am - 5:00pm

Why does the catalytic combustor stop working?

A catalyst does not burn out like a light bulb.
Most catalytic combustors that are returned are either destroyed by flame impingement, broken due to accidents or mishandling, or there is nothing wrong with them but fly-ash build up.
A catalyst can be "saturated" with byproducts of wood burning such as potassium. This is chemical saturation. The prohibitive chemical will fill the chemical "holes" that the gases normally use for reaction.
This process of saturation can be slowed by regular maintenance of the catalyst.
Saturation can take several years, most units will last for a minimum of six year or 12,000 operating hours.