Air Preheater (APH) 4 MAJOR ADVANTAGES OF AIR PREHEATER IN BOILER : 1 . Increased thermal efficiency 2. Short payback period & increased combustion rate 3. In the case of combustion of pulverized coal hot air can be used for drying the coal as well as for burning the coal efficiently 4. All standard fuels and even lower grades of coals can be burnt efficiently with hot air Thermodyne Boilers is a successful manufacturing the Boiler accessories like Air Preheaters, Economizers , Superheaters etc.