Convett has completed the entire range of cooling systems with the manufacturing of expandable radiators for distribution transformers. For transformers with a size between 4MVA to 12MVA some manufacturers prefer to propose to their customers a sealed transformer without conservator, instead of using the classic radiators and the conservator. Using the expandable radiators mounted on the top of the corrugated wall tank you can increase the cooling dissipation surface maintaining the elasticity of the entire cooling system. This allow a cost reduction due to the elimination of the conservator, the reduction of the number of valves, the reduction of labour to mount the radiators and in the end a reduction of the overall dimensions of the transformer. Painting testing report is issued for every environmental class category and a complete leakage test is run on the radiator.