A wood stove combustor uses honeycomb-like cells to trap and reburn smoke particles and flue gases through a chemical reaction. This extends the amount of heat produced from each load of wood and reduces pollution particles emitted from the chimney.
How Combustors Work:
Most of the combustors we sell are ceramic, but some combustor manufacturers offer a steel option. In our opinion, the ceramic is a better investment because ceramic is less likely to clog or warp. Not all wood stoves use a combustor, but if your stove does have one, it’s important to never burn trash, painted or treated lumber, or lighter fluid since these can poison the combustor.
What is the difference between a canned and uncanned combustor?
There are 2 types of ceramic combustors. The main difference comes down to the presence or absence of a metal band referred to as the “can.”
Canned Combustors – These include a strip of stainless steel wrapped around the edge of the combustor with a flat interam gasket layered between the ceramic combustor and the metal band. The metal band boosts the catalytic process in the stove by accelerating the reaction that breaks down the smoke particles and flue gases.
Uncanned Combustors – These include simply the ceramic combustor. This type of combustor requires an interam gasket which is sometimes sold separately. The flat, wide interam gasket expands when the stove heats up and seals the space around the combustor to prevent smoke and flue gases from bypassing the combustor.
Will my new combustor need a gasket?
Canned combustors already come with a layer of gasket inside the metal band and usually do not need another layer of interam gasket. Uncanned combustors will need a layer of interam gasket to fit and function in the stove properly. Wrap the flat strip of gasket around the outer edge of the combustor so that the ends meet snugly. Secure with a piece of masking tape. The heat of the first fire will burn away the tape, and the gasket will expand to fill the space around the combustor.
How often should the combustor be replaced?
The catalytic combustor should be replaced after 12,000 hours of burn time, or after 6 years of use, whichever comes first. Depending on the length of winter and frequency of use, the combustor may need to be replaced sooner than 6 years. Watch for these 4 common signs that the combustor may be ready for replacement:
1. Decreased Heat Output – Less heat emitted by the stove is an early sign of combustor failure. Use a catalytic thermometer to measure whether the combustor is slow to reach catalytic temperatures, and if the combustor heats to the same heat level as it has in the past.
2. Creosote Accumulation – A significant accumulation of creosote on the chimney walls indicates the catalyst is not breaking down the smoke and flue gases completely during the catalytic reaction. The chemical coating of the combustor could be “poisoned” by burning improper fuel, or there could be damage such as cracks or crumbling combustor cells. In either case, the combustor will need to be replaced.
3. Sluggish Performance – Poor draw of air into the stove when engaging the combustor is another classic sign that the combustor may be failing. Check the combustor for clogged cells.
4. Smoke Emitted from the Chimney – Smoke from a healthy catalyst will appear white in color. Significant amounts of dark smoke from the chimney when the combustor is engaged indicates the combustor is no longer breaking down those flue gasses effectively.