Boiler-filter assembly comprising a boiler and a filter suitable for filtering the water that flows into the boiler in order to remove any residues from the water; said filter comprising: - a cylindrical body comprising a lateral surface, a first end wall, a second end wall and a longitudinal axis; said body comprising a first mouth and a second mouth obtained on the lateral surface; said first mouth being intended to be connected to a water system and said second mouth being connected to the boiler; - a pipe arranged in the body in communication with the exterior; - a magnet inserted in the pipe to hold ferrous residues contained in the water; said boiler-filter assembly comprising a three way valve comprising: - a first port connected to the first mouth of the body; - a second port intended to be connected to the water system; - a third port used to discharge the water; - a diverter suitable for being in a first position, wherein the diverter closes the third port of the three way valve, and in a second position, wherein the diverter closes the second port of the three way valve; wherein said first mouth and said second mouth of the body of the filter are tangent to the body, being aligned and disposed on the same side of the body relative to a plane passing through the longitudinal axis of the body of the filter; characterized in that said filter comprises: - a drum suitable for holding non-ferrous residues; and - a disk disposed in the pipe and comprising a plurality of openings with variable helical geometry. - a cylindrical body comprising a lateral surface, a first end wall, a second end wall and a longitudinal axis; said body comprising a first mouth and a second mouth obtained on the lateral surface; said first mouth being intended to be connected to a water system and said second mouth being connected to the boiler; - a pipe arranged in the body in communication with the exterior; - a magnet inserted in the pipe to hold ferrous residues contained in the water; said boiler-filter assembly comprising a three way valve comprising: - a first port connected to the first mouth of the body; - a second port intended to be connected to the water system; - a third port used to discharge the water; - a diverter suitable for being in a first position, wherein the diverter closes the third port of the three way valve, and in a second position, wherein the diverter closes the second port of the three way valve; - a first port connected to the first mouth of the body; - a second port intended to be connected to the water system; - a third port used to discharge the water; - a diverter suitable for being in a first position, wherein the diverter closes the third port of the three way valve, and in a second position, wherein the diverter closes the second port of the three way valve; wherein said first mouth and said second mouth of the body of the filter are tangent to the body, being aligned and disposed on the same side of the body relative to a plane passing through the longitudinal axis of the body of the filter; characterized in that said filter comprises: - a drum suitable for holding non-ferrous residues; and - a disk disposed in the pipe and comprising a plurality of openings with variable helical geometry. - a drum suitable for holding non-ferrous residues; and - a disk disposed in the pipe and comprising a plurality of openings with variable helical geometry.