Operation of stove of blast furnace has been considered. The stove has been equipped with external chamber of combustion. Highly reliable ceramic burners are used in the stove. Application of the new burners requires to determine new optimal parameters of operation. In connection with this, mathematical model of the burner systems has been developed with the use of differential equations. Equation of heat conduction has been varied and heat transfer in the chamber height has been taken into account. Processes of arising the thermal stresses in refractory materials have been analyzed. Various parameters have been calculated and measured. Calculation results agree with experimental data.