A sudden rise in chimney temperature without an increase in load indicates what condition?

A sudden rise in chimney temperature without a corresponding increase in load can indicate a broken baffle. Baffles in a boiler or combustion system help direct the flow of flue gases and reduce losses, ensuring efficient heat exchange. When a baffle is damaged or broken, flue gas may flow too quickly and not allow enough time for the heat exchange to occur efficiently. This leads to higher temperatures in the chimney as heat escapes without being utilized in the system.

In contrast, other conditions like excessive combustion or insufficient air supply generally manifest through changes in fuel or air consumption, which would typically be reflected in the load conditions or could cause other malfunctions rather than just affecting the chimney temperature directly. Similarly, a malfunctioning safety valve would typically lead to other operational signs such as unexplained pressure changes or valve opening due to excess pressure, rather than simply an increase in chimney temperature.