A submerged combustion melting system (90) includes a submerged combustion melter (100) having a housing with one or more side walls (104), a floor (106), and a ceiling (108) which at least partially define a melt chamber (110). The melter has one or more main burners (128) positioned along the floor of the housing and an oxygen/gas burner in a preheat burner system (300) removably attached to one of the sidewalls or the ceiling, the oxygen/gas burner arranged such that a flame from the oxygen/gas burner is directed downward into the melt chamber.