A cooling assembly for a metallurgical furnace includes a cooling plate disposed inside of a furnace shell of the metallurgical furnace; a cooling pipe traversing a shell opening in the furnace shell and being connected to the cooling plate; and a compensator disposed around the cooling pipe for forming a seal between the cooling pipe and the furnace shell. In order to provide ways for facilitating repair of a cooling system of the metallurgical furnace, the method includes at least the step of performing at least one cutting operation with a cutting device having a fixture and a cutting tool movably connected to the fixture for a guided movement with respect to the fixture. The fixture is mounted to the cooling pipe, whereby the cutting device is aligned with respect to the cooling pipe, and the cutting tool is guidedly moved while performing the cutting operation.