Abstract: The invention is directed to a balanced flue or direct vented, solid fuel burning fireplace which may be installed in a building and is operable at energy input levels greater than 75,000 BTU/hour. An enclosure including a top wall, bottom wall and four side walls defines a combustion chamber. At least one of the side walls includes an operable, sealed, transparent access door. A flue is connected to the enclosure and disposed in fluid communication with the combustion chamber and an outside ambient environment external to the building. A combustion air duct is connected to the enclosure and disposed in fluid communication with the combustion chamber and the outside ambient environment external to the building, whereby substantially all of the combustion air supplied to the combustion chamber flows through the combustion air duct when the access door is in a closed position.

Abstract: A thermally activated vent damper assembly for a flue is adapted to be situated in relation to the flue for occluding the passage of gas through the flue. A support member traverses the flue and suspends the damper member across the flue for movement between an open and a closed position. A thermally activated biasing member is operatively coupled between the support member and the damper member to bias the damper member in the open position in the presence of heat and to bias the damper member in the closed position in the absence of heat. The coupling of the biasing member between the support member and the damper member is such that potential sites for frictional inhibition of damper member movement are eliminated. Upon breakage or other failure of the biasing member to apply bias, the damper member defaults to or remains in an open position under the force of gravity, providing for a unique fail-safe feature.

Abstract: A thermally activated vent damper assembly for a flue is adapted to be situated in relation to the flue for occluding the passage of gas through the flue. A support member transverses the flue and suspends the damper member across the flue for movement between an open and a closed position. A thermally activated biasing member is operatively coupled between the support member and the damper member to bias the damper member in the open position in the presence of heat and to bias the damper member in the closed position in the absence of heat. The coupling of the biasing member between the support member and the damper member is such that potential sites for frictional inhibition of damper member movement are eliminated. Upon breakage or other failure of the biasing member to apply bias, the damper member defaults to or remains in an open position under the force of gravity, providing for a unique fail-safe feature.