Boilers type Primula R with power range 20-300kW are ment for combustion of liquid and gas fuel with the use of fan burners.Coupling the boiler with fan burners on liquid or gas fuel gives maximal boiler output and boiler efficiency of 90-92%.

                Boiler is constructed as „three drafted“ with reversible fire tube and flue pipes which means that products of combustion pass water area in three occasions maximasing the heat exchange.First and second heat exchange are in the reversible fire tube, mostly by methods of irradiation and the third heat exchange is in flue pipes before the flue gasses exit the boiler mostly by methods of conduction and convection.Because of the use of fan burners, turbulators are installed into flue pipes which maximases the heat exchange between the flue gases and water and increases the boiler efficiency. Construction of the boiles is such that provides free dilatations of fire tube and flue pipes which as a result has that these boiler can easily stand the sudden heat regime changes.Boiler body is well insulated with mineral wool and boiler sheeting is protected with painting or powder coating processes.

                Boiler is ment for production of hot water in operating mode 110/90ºC and 90/70ºC with maximum allowed work pressure of 2,5bar (for 20-60kW boilers) and 3 bar (for 80-300kW boilers)

                Regulation of air flow needed for combustion is done through the burner and boiler automatic controler.

                Protection of boiler from increased pressure is done by installing the safety valve on the appropriate place on the boiler.