Burner installation in a steam generator having means for firing pulverized coal as well as gas, includes a combustion chamber of substantially rectangular cross section, at least three pulverized coal-burners disposed mutually adjacent one another in cross-sectional direction of the combustion chamber on a first wall of the combustion chamber at least one of the pulverized coal-burners being located between others thereof, gas burners located on at least another wall of the combustion chamber located adjacent the first wall thereof, the pulverized coal burners being located at an elevation of the combustion chamber above the gas burners, the at least one of the pulverized coal-burners being operable only if gas is not being burned simultaneously therewith by the gas burners.