Abstract: A heater comprises a casing, which has an interior chamber. It further comprises a rotor, which is formed as an impeller on the one hand and as an eddy-current disk on the other, and a magnet support, which is equipped with permanent magnets and disposed non-rotarily in the casing and which is displaceable into an operating position in the direct neighborhood of the eddy-current disk and into a position of rest spaced therefrom. The eddy-current disk and the magnet support equipped with permanent magnets are rinsed by water.

Abstract: A flue insulation assembly comprising an insulation lining surrounding the flue wall in spaced relationship and composed of insulation elements retained by a mounting structure. The insulation lining is composed of a plurality of plate-shaped insulation elements laterally abutting one another so as to form a near-annular polygon, and the mounting structure is composed of vertically spaced mounting rings connected to the flue wall by mounting ring supports and adapted to retain the insulation elements therebetween. The mounting rings are provided with stop elements projecting over the upper and lower rims of the plate-shaped insulation elements on both sides thereof, and an outer skin is secured to the mounting rings.