If a stack temperature is higher than normal after maintenance, what could be a possible cause?

When the stack temperature is higher than normal following maintenance, the presence of defective or missing baffles can significantly impact the system's efficiency. Baffles are essential components in flue gas paths that help direct the exhaust gases and promote proper heat exchange within the boiler or system. If these components are damaged or absent, it can lead to improper airflow, resulting in poor combustion and incomplete burning of fuel. This inefficiency can cause the stack temperature to rise as excess heat is not being utilized effectively within the system. Therefore, focusing on the integrity of the baffles is crucial in diagnosing high stack temperatures after maintenance activities.