Abstract: A burner for use in burning granulated solid fuel including a burner head having a combustion chamber and inlet and outlet openings at opposite ends thereof communicated with the combustion chamber. Means is provided to deliver granulated solid fuel to the inlet opening and means is provided for delivering primary combustion air to the inlet opening. The primary combustion air is preheated by passing along the burner head prior to entry to the inlet opening and a pilot assembly in the combustion chamber maintains a constant pilot during turndown of the burner. A retention barrier in the combustion chamber retains fuel particles larger than a predetermined size in the combustion chamber to insure complete incineration thereof.

Abstract: A control circuit for a solid fuel furnace which includes a combustion chamber, means for delivering solid fuel to the combustion chamber, and means for delivering combustion air to the combustion chamber, wherein the control circuit includes thermo-sensitive means responsive to a demand temperature and to a temperature related to furnace performance to control the fuel delivery means and the combustion air delivery means for maximum furnace efficiency, minimum fuel consumption and minimum soot and smoke formation. In addition, the control circuit includes "hold fire" circuit which is operable in response to combustion-related temperatures and during periods when the demand temperature is met to control the fuel delivery means and the combustion air delivery means to maintain combustion in the combustion chamber.

Abstract: A solid fuel furnace which includes a housing enclosing a firebox and a heat exchanger chamber. An open grate in the firebox supports solid fuel thereon. Combustion air is admitted to the area below the grate and is preheated and passes upwardly through the grate and fuel and mixes with volatile gases released from the fuel. The air/gas mixture is drawn downwardly through the fuel and exits the firebox through an inlet to an insulated burn-out chamber which is behind the firebox. A metal screen covers the inlet and serves to ignite the air/gas mixture. Hot flue gases exit the burn-out chamber to the heat exchanger chamber.

Abstract: A solid fuel furnace which includes a housing enclosing a firebox and a heat exchanger chamber. An open grate in the firebox supports solid fuel thereon. Combustion air is admitted to the area below the grate and is preheated and passes upwardly through the grate and fuel and mixes with volatile gases released from the fuel. The air/gas mixture is drawn downwardly through the fuel and exits the firebox through an inlet to an insulated burn-out chamber which is behind the firebox. A metal screen covers the inlet and serves to ignite the air/gas mixture. Hot flue gases exit the burn-out chamber to the heat exchanger chamber.