Method for detecting blockage in exhaust flue of gas boiler

A method for detecting a blockage in an exhaust flue of a gas boiler, which drives a blower according to an amount of air flowing through a venturi provided at a blower inlet when the boiler is activated and thereby introduces gas, and conducts an ignition process via a controller after an air-gas mixture, which is a mixture of introduced gas and air, is supplied to a burner, wherein the controller detects temperatures of supplied heating water and collected heating water during heating by temperature sensors provided in a supplied heating water pipe and a collected heating water pipe, and uses a fan RPM of the blower and the temperatures of supplied heating water and collected heating water to detect the blockage in the exhaust flue, the method comprising,

• (A) a step for conducting, by the controller, the ignition process according to a user set temperature and performing temperature control to reach the user set temperature;
• (B) a step for determining, by the controller, whether a current fan RPM of the blower exceeds a reference fan RPM which is set as a value less than a maximum fan RPM, after a holding time elapsed;
• (C) a step for calculating, by the controller, a difference between temperature values of supplied heating water and collected heating water detected by the temperature sensors when heating water is supplied, and determining whether the difference is less than a reference temperature value, when it is determined that the current fan RPM exceeds the reference fan RPM, wherein the reference temperature value is determined by operating the gas boiler when the blockage is not detected in the exhaust flue, by adjusting the fan RPM of the blower, by gradually blocking the exhaust flue, and by obtaining a value of temperature difference between supplied heating water and collected heating water at a blockage point determined by observing combustion performance, a carbon monoxide level, and a flame condition of the gas boiler;
• (D) a step for determining, by the controller, whether a preset time has elapsed from a time point in step (C) when it is determined that the difference is less than the reference temperature value;
• and
• (E) a step for displaying, by the controller, on a display, a notification that the blockage in the exhaust flue has been identified when it is determined that the preset time has elapsed.