A pellet burner feeds wood pellets into a small, hot fire. Use the buttons to look inside, then follow the fuel from the hopper, through the flame, and out as useful heat.
A pellet burner is a stove or boiler that burns small compressed wood pellets instead of logs or gas. At its centre is a combustion chamber: a small, open pot where the fuel burns hot under a steady blast of air, feeding its heat to a heat exchanger.
The fire itself is hidden behind the stove casing, and the parts that make it work — the auger, the air fan, the igniter — are tucked out of sight. Cutting the casing open shows how fuel, air and heat move through the machine.
The hopper is the fuel store on top of the stove. Wood pellets sit in it and fall down through a tapered funnel into a feed tube, ready to be carried to the fire.
A screw-shaped auger turns slowly and pushes pellets along a tube into the burn pot. Because it turns at a set rate, it delivers a steady, measured stream of fuel rather than dumping it all at once.
A combustion-air fan blows air up through small holes in the floor of the pot. An electric igniter glows hot and lights the incoming pellets; once the flame is burning steadily, the igniter switches off and the fire sustains itself.
The flame burns in the open pot, and its hot combustion gases rise straight into the heat exchanger above. There the gases pass over a large metal surface and give up their heat to water or air on the other side.
Once most of its heat has been taken out, the cooled gas leaves through the exhaust flue. Meanwhile, the ash left from burning drops over the edge of the pot into a pan below, to be emptied later.
No. They burn compressed wood pellets — small, dense cylinders made from sawdust and wood waste. Their uniform size and low moisture let the auger feed them at a steady, controlled rate.
The holes let combustion air blow up through the fuel bed. Air feeding the base of the fire makes the pellets burn hot and cleanly, instead of smouldering from the top down.
An electric igniter — a heated element at the base of the pot — glows hot for a few minutes until the incoming pellets catch. Once the flame is established, the igniter switches off.
Hot combustion gases rise from the flame through a heat exchanger, which transfers their heat to water or air. The cooled gases then leave through the exhaust flue.
Ash left behind after burning falls through or over the edge of the pot into a pan below. The pan is emptied periodically, far less often than a log fire would need.