Abstract: A method for controlling gas flow direction through a regenerative incinerator system coupled to a flow reversing valve, and for reversing the flow direction of the gas stream through the regenerative incinerator system. The regenerative incinerator system having a combustion zone and one or more heat accumulating and heat exchanging zones. The method establishes a combustion zone base temperature set-point, or T.sub.CB for referencing combustion zone temperatures, or T.sub.C 's, and an outlet base temperature set-point, or T.sub.OB, for referencing outlet temperatures, or T.sub.O 's, from the regenerative incinerator system. A switching temperature, or T.sub.S, is also established as a function of T.sub.C, T.sub.CB and T.sub.OB such that the slope of said function, i.e. dT.sub.S /dT.sub.C, is never negative over a predetermined range of combustion zone temperatures, or T.sub.C 's. The switching temperature being equal to T.sub.OB when the combustion zone temperature is equal to T.sub.CB.