Abstract: A combustion system includes a primary combustion chamber divided into left and right sides by fuel-retaining standards defining a canyon or void extending into a secondary combustion chamber is provided. The floor of the primary combustion chamber and the fuel-retaining standards direct the burning solid fuel toward the lower part of the canyon, while at the same time retaining the non-burning solid fuel on either side of the fuel-retaining standards. The combustion system further includes an air delivery system having a lower air tube supplying high and low velocity air and an upper air tube. The lower air tube is positioned proximate to a firebox floor, while the upper air tube is positioned within the secondary chamber. Automatic air setting mechanisms are provided so that proper air settings can be maintained during various phases of a fire.