Abstract: A deep fat fryer is disclosed that employs an interior array of heat exchanger tubes arranged in a "U" configuration along the sides and back of the vat. The heat exchanger tubes are located in the interior of the vat with the ends attached to the front vat wall. Combusting fuel and oxygen are directed through the heat exchanger tubes using either a premix burner located at one end of each tube or by using an atmospheric burner generally adjacent to one end of each tube and inducing a draft through each tube. The combustion gases produced by the burners travel through the heat exchanger tubes and exit into a combustion channel. The combustion channel directs the gases exiting the heat exchanger tube around and in contact with at least a portion of the exterior wall of the vat and then to an exhaust flue at the rear of the vat.