Abstract: The present invention provides a novel system for monitoring a predetermined operating condition of a heating apparatus, such as a cumulative total time period of combustion and a combustion frequency, and informing a user of a timing of maintenance. In a hot water heater (1) according to the invention, a controller (208) outputs a maintenance requirement signal to a display (210) and a maintenance alarm to inform the user of a timing of maintenance when a combustion frequency nx becomes equal to or greater than a first reference value nr1 or when a cumulative total time period of combustion tx becomes equal to or greater than a second reference value tr1. This allows the user to perform maintenance without delay and prevents troubles or abnormalities from being developed in the hot water heater (1).

Abstract: A safety device for a combustion apparatus comprises a continuous, linear temperature-sensing element formed of a material which is electrically conductive and melts, or breaks, at a relatively low temperature and located along at least one side of a combustion chamber of a combustion apparatus and one side of a heat exchanger thereof. The temperature-sensing element is electrically connected to a combustion control circuit such that, if and when the combustion chamber or the heat exchanger has reached an extremely high temperature, the temperature-sensing element melts, or breaks to cause said combustion control circuit to stop a combustion in said combustion chamber. Lead, tin, or an alloy of lead and tin may be employed as the material of the temperature-sensing element.