Abstract: A furnace includes a pump in a circuit through a heat exchanger and a manifold having a plurality of discharge openings in a first area and return openings in a second area connected by a transfer area with each discharge and return feeding a respective heat loop. A bypass in the circuit includes a temperature controlled protection valve connected between the bypass and the manifold. The heated liquid inlet of the manifold is connected to the manifold in the first area with the plurality of discharge openings at a position between the plurality of discharge openings and the plurality of return openings. The manifold is defined by a rectangular chamber divided longitudinally and diagonally by a transverse wall which terminates at one end at a position spaced from an adjacent end of the chamber to define an undivided portion of the chamber at the end which forms the transfer area.

Abstract: A boiler apparatus having a combustion chamber, a container for receiving liquid to be heated, a flue, and tubes passing through the container to join the combustion chamber and flue includes a tube cleaning system comprising outer edges of turbulators that are in contact with the respective inner tube surface, a horizontally extending shaft over the tubes, and pivotal connections by which the downwardly depending turbulators are connected to the shaft. The shaft defines an axis about which it is pivotal, where by pivoting of the shaft the turbulators are moved relative to the tubes in vertical longitudinal sliding movement from an operating position to a raised position and back thereto so as to generate a cleaning action against the inner tube surface. Each turbulator is removably attached to the shaft independently of the other allowing each to be removed for cleaning without disassembling a remainder of the tube cleaning system.

Abstract: A boiler assembly including primary and secondary combustion chambers includes primary and secondary air controls for controlling combustion air to the chambers respectively. The air controls are operable between open positions to allow combustion in the chambers and a closed position in which the combustion air passages are fully sealed to fully interrupt combustion responsive to heating demands. The air controls are supported externally on the main housing of the boiler assembly so as to be modular and readily releasable from the main housing and the respective combustion air passages. The primary combustion chamber communicates with the secondary combustion chamber at a location partway in between introduction of the secondary combustion air and the exhaust passage.