Abstract: According to the invention the heating system for regenerative coke oven batteries that can be heated with rich gas and/or lean gas or mixed gas is provided comprising vertical flues cooperating in pairs, each vertical flue being connected to a regenerator for preheating the air and, in the case of lean gas operation, for preheating the lean gas or mixed gas. High and low combustion stages, as well as structure defining an internal flue gas return at levels above a flue base are provided. Discharge openings are provided at at least three levels for supplying each flue. A base discharge opening is provided at the flue base directly connected to regenerators. Hollow communicating channels are defined for connecting the regenerators to discharge openings located above the flue base. The hollow communicating channels are preferably formed in each communicating wall connected to a discharge opening leading only to one adjacent flue.