Measuring Airflow using the Temperature Rise Method
The Temperature Rise Method (Sensible heat formula)
For an electric furnace the airflow measurement procedure is the same. Allow the appliance to operate until the temperature rise stabilizes. Measure the temperature rise again out of the line of sight of the electric heater, along with the incoming volts and current draw in amps to the electric strip heaters. Enter the information into the following formula.
For fuel oil the procedure involves verifying the nozzle size and the correct fuel pressure. After the Nozzle size in GPM (gallons per minute) is known and fuel pressure set, the combustion efficiency must be measured with a stable stack temperature, and the temperature rise across the heat exchanger recorded.