What does the Gross Stack Temperature measure?

The Gross Stack Temperature measures the flue gas temperature upstream of the draft hood. This temperature is critical for evaluating the efficiency of combustion processes and determining heat loss in exhaust systems. By measuring the temperature before the gases pass through the draft hood, technicians can assess how effectively the appliance is operating and identify potential issues. Accurate measurement at this point allows for better control of combustion air and optimization of the combustion process, which is essential for maintaining safety and efficiency in gas appliances.

While other options mention downstream temperatures or ambient conditions, these do not give an accurate representation of the gases exiting the combustion process nor their efficiency, which emphasizes the importance of understanding Gross Stack Temperature in practical applications.