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NORA Oilheat Technicians Manual

Chapter 7 Combustion Study the instruction manual and take the time to learn how your analyzer works before you expect it to perform for you. Be sure to follow the manufacturer’s recommended maintenance and service procedures. 7-24 Combustion measure the temperature of the flame due to dilution of the gases and absorption of the heat by radiation to the surrounding areas, we use a combustion equation to determine the quality of the combustion process. The efficiency calculation is based upon the theoretical heat value of the fuel being burned minus the stack losses. To calculate the combustion efficiency with older test equipment, you need to know: 1. The Net Stack Temperature: This is the measured or gross temperature as indicated by the stack thermometer, minus the ambient or intake air temperature. 2. The % CO2 in the Stack Gases: Do not use the % CO2 measured over the fire. This is for air leak checks only. Test the CO2 at the breech. To calculate the steady state efficiency, use combustion efficiency tables or the combustion efficiency slide ruler. Adjust the large slide to the right so that the net stack temperature appears in the small window in the upper right corner marked “Net Stack Temperature”; then move the small vertical slide until the arrow points to the CO2 reading. Through the window in the arrow on this slide you now read the figures: combustion efficiency in black and on-cycle heat loss in red. Electronic combustion test equipment One drawback of manual combustion test instruments is the time required to use them properly. This is especially true when the tests must be repeated during oilburner fine-tuning. New digital electronic testing instruments have been developed in recent the center of the flame in the combustion chamber. Place the rubber connector end of sample pump on top of valve and push it down to open the valve. Squeeze and release the rubber bulb 18 times to pump combustion gases into the analyzer. Release the valve while the bulb is still collapsed on the 18th stroke, and remove the rubber connector from the instrument. C. Tip the analyzer completely over and back twice, allowing gas to bubble completely through the fluid. Hold at 45 degree angle for 5 seconds to complete draining of fluid. The fluid has now absorbed the CO2 from the gas sample, and has been pulled up in the center tube. Hold the analyzer upright and read the CO2 on the scale opposite the top of the fluid. D. Depress the valve on top of analyzer several times, release, and check to see that the zero setting has not changed. If it has, repeat the above steps. E. If the CO2 analyzer is cold, run one or two tests to warm it up before using the reading. NOTE: The CO2 test fluid is hazardous. Do not invert analyzer while the plunger valve is depressed. If fluid gets on your hands, wash them immediately. Combustion efficiency calculations Since it is not possible in the field to


NORA Oilheat Technicians Manual
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