The type ATDA and ATDG fan-assisted unit heaters are designed for heating and ventilating industrial, workshop, retail and warehouse premises, garages, supermarkets and similar spaces. The unit heater is available in two versions: for hot water (ATDA) and for steam (ATDG). Both types of unit heater incorporate a corrosion resistant heating coil consisting of aluminium fins and copper tubes. The ATDA and the ATDG units are available in three different sizes (the ATDA in four different capacity variants) for various air flow rates and capacity demand, which cover most of the conditions under which the unit operates.