The ST 50 is a 20-56KW, 69000-190000 BTU Oil Burner. Sterling Oil Burner. Nu-Way oil burners are known for their sturdy reliability. Sterling burners are fitted to a number of light oil boilers. As the burner uses reliable manufacturers parts like Danfoss oil pumps, Danfoss transformer and Satronic control box this in turn this gives the burner a long life. This burner has a full removable inspection plate that allows full access for ease of maintenance.