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This paper describes common temperature control schemes for gas melting furnaces. A scheme for a closed loop control is introduced. Normally controllers are implemented for the control of the power of the systems that utilize only one of the temperatures mentioned. This temperature is driven to a given set point by modulating the power of the burners; the other temperature will, when reaching an upper limit value, switch of the burners completely. Other temperature measurements may also lead to cut-off of burners. A control scheme, known as override control, is introduced, that uses more than one process value to control the power of the burners. These process values may be the temperature of the ceiling of the furnace, the temperature of the hot flue gas and in addition the temperature in the stack. The paper will be published in two parts. This first part deals mainly with the theoretical basics. The second part of the article will compare a simple control scheme just based on the ceiling temperature of the furnace to a more sophisticated override control scheme. [ABSTRACT FROM AUTHOR]