A method for monitoring a coaxial double safety valve of a gas valve unit of a valve monitoring system, wherein the gas valve unit regulates a gas request of a gas burner occurring in the course of a heat request, and the gas valve unit has at least the coaxial double safety valve and a control valve which is fluidly connected downstream therefrom in series in order to regulate the amount of gas, wherein the double safety valve has a first integral control valve and a second integral control valve that is arranged coaxially and fluidically downstream from the first control valve, each of which can be controlled exclusively between an open position and a closed position, wherein a gas inlet pressure acts on the inlet side of the first control valve, wherein a pressure sensor or pressure switch measuring a switching pressure is arranged in a flow space that is formed between the first and the second control valve (4, 5), and wherein, by successively checking the switching pressure, a tightness test of the second control valve and of the first control valve is respectively performed in dependence on an open position or closed position of the control valve and the open position or closed position of the first and the second control valve (4, 5), characterized in that the method passes through the following steps during the gas request in the course of the heat request: a) the first and the second control valve (4, 5) are brought into the open position for a predetermined time interval and, immediately thereafter, into the closed position, b) the control valve is brought into the open position, c) the switching pressure in the fluid space is checked and compared with a pressure threshold value in order to test the second control valve for tightness, d) the first and the second control valve (4, 5) are brought into the open position, e) upon fulfillment of the gas request, the first and the second control valve (4, 5) are brought into the closed position, and then the control valve is brought into the closed position, f) the switching pressure in the fluid space is checked and compared with a pressure threshold value in order to test the first control valve for tightness. wherein the double safety valve has a first integral control valve and a second integral control valve that is arranged coaxially and fluidically downstream from the first control valve, each of which can be controlled exclusively between an open position and a closed position, wherein a gas inlet pressure acts on the inlet side of the first control valve, wherein a pressure sensor or pressure switch measuring a switching pressure is arranged in a flow space that is formed between the first and the second control valve (4, 5), and wherein, by successively checking the switching pressure, a tightness test of the second control valve and of the first control valve is respectively performed in dependence on an open position or closed position of the control valve and the open position or closed position of the first and the second control valve (4, 5), characterized in that the method passes through the following steps during the gas request in the course of the heat request: a) the first and the second control valve (4, 5) are brought into the open position for a predetermined time interval and, immediately thereafter, into the closed position, b) the control valve is brought into the open position, c) the switching pressure in the fluid space is checked and compared with a pressure threshold value in order to test the second control valve for tightness, d) the first and the second control valve (4, 5) are brought into the open position, e) upon fulfillment of the gas request, the first and the second control valve (4, 5) are brought into the closed position, and then the control valve is brought into the closed position, f) the switching pressure in the fluid space is checked and compared with a pressure threshold value in order to test the first control valve for tightness. a) the first and the second control valve (4, 5) are brought into the open position for a predetermined time interval and, immediately thereafter, into the closed position, b) the control valve is brought into the open position, c) the switching pressure in the fluid space is checked and compared with a pressure threshold value in order to test the second control valve for tightness, d) the first and the second control valve (4, 5) are brought into the open position, e) upon fulfillment of the gas request, the first and the second control valve (4, 5) are brought into the closed position, and then the control valve is brought into the closed position, f) the switching pressure in the fluid space is checked and compared with a pressure threshold value in order to test the first control valve for tightness.