Rotary Air preheater recovers the heat from the flue gas from the boiler going to the chimney and transfers the same to the combustion air to the boiler thus reducing the fuel consumption of the boiler. The efficiency of Rotary Air preheater is very high compared to the Tubular air preheater and also it occupies less space for the same heat recovery when compared with the Tubular Air preheater. Air preheater rotor is divided into compartments in which the heating elements are packed. Heating elements in the Air preheater plays a major role for the heat transfer from the flue gas to the combustion air. The leakage from the flue gas to the combustion air is reduced by Radial, Axial and Circumferential seals thus reducing the fan loading.