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NORA Oilheat Technicians Manual

Percent Excess Air Percent Excess Air Correlation of Percent of CO2, O2 and Excess Air Carbon Oxygen Excess Air Dioxide (Approx.) 15.4 0.0 0.0 15.0 0.6 3.0 14.5 1.2 6.0 14.0 2.0 10.0 13.5 2.6 15.0 13.0 3.3 20.0 12.5 4.0 25.0 12.0 4.6 30.0 11.5 5.3 35.0 11.0 6.0 40.0 10.5 6.7 45.0 10.0 7.4 50.0 The ranges that you will use most frequently are bold-faced and in color. Chapter 7 Combustion Figure 7-21: Relationship of CO2, O2 and excess air Chapter 7—Combustion 7-21 Percent CO2 Percent O2 (Oxygen) Flame impingement The flame must not touch any solid surfaces of the burner, the end cone, the combustion chamber, or the heat exchanger. If this happens, the flame will be cooled and the unburned carbon atoms will turn to smoke and soot. Possible causes: • Overfiring, too large a nozzle or excessive oil pump pressure • Incorrect oil and/or air pattern • Burner installed too high, too low, or off center • Incorrect combustion chamber size or shape, or base of the chamber full of soot • Partially plugged nozzle • Cold oil Smoky shut down Check the cut-off valve by using a pressure gauge in the fuel pump nozzle port. See the nozzle and fuel unit chapters for causes of after drip. (Chapters 4 and 5). Excess air: CO2 and O2 As we add excess combustion air, the amount of nitrogen and unburned oxygen increase. The amount of water and carbon dioxide remain the same because we have already burned all the fuel; therefore the


NORA Oilheat Technicians Manual
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