UP-900 is a pre-heating chamber, equipped with an exclusive Keraglass system, which is positioned between the loading roller conveyor and the heating chamber. It allows to pre-heat the glass sheets at a temperature of about 400/500 °c, before entering the main heating area. A forced convection heating system is used, with hot pre-heated closed-circuit air to minimize consumption. This type of heater is suitable for all types of new generation low-emissive glass as well as for thick glass, avoiding unexpected breakage in the heating chamber. It is conceived to guarantee a better optical quality of glass and, besides allowing the tempering of last generation low-emissive glasses, it has the advantage of shortening the float glass heating cycle from 40 sec/mm to 30 sec/mm, with a production increase of 25%.