FOUR-RAP Radial Apparatuses are designed for use in large volumes that need heating and cooling, such as factories, workshops, garages, sheds, gyms. Hot water, steam and electrical energy are used as heat sources. FOUR-AAP series devices with axial fans are more suitable for use in rooms with a ceiling height of 4 m. If the room height is more than 4 m, the FOUR-RAP series with radial fans should be preferred. The FOUR-AAP and FOUR-RAP series heater units are created by combining specially designed covers made of galvanized sheet metal. The inner and outer surfaces are painted with electrostatic powder coating. Aluminum finned heater batteries with copper tubes are used in the FOUR-AAP and FOUR-RAP series. Standard copper pipe up to 90/70 °C hot water and 2.0 Atu steam pressure and thick fleshy copper pipe up to 4 Atu steam pressure are used. At a steam pressure of 8 Atu, steel pipes, serpentines with steel blades are used.