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NORA Oilheat Technicians Manual

7-10 Combustion how much improvement you have made in the combustion efficiency, and how much money you have saved your customer. Combustion test equipment Combustion testing equipment can be separated into two groups: the manual instruments (Figure 7-7), and the continuous sampling digital electronic instruments, Figure 7-8. The manual equipment has been older units, there is no way you can accurately determine whether the chemical reaction is complete by just observing the fire. The most important setting you make on the burner is excess air. You cannot really do this without instruments. If you give testing a fair trial, you will find it will reduce the time required to accurately service, troubleshoot, and adjust a heating system. Principles of combustion testing Combustion test instruments measure the composition and temperature of flue gases as they leave the boiler or furnace. We use this information to calculate the amount of excess air and the combustion efficiency. We also measure the amount of smoke and draft produced in order to properly adjust the flame and identify problems. Combustion testing measurements: • Temperature of the flue gases • Draft produced by the chimney, power-venter or venting system • Smoke concentrations in the flue gases • Composition of the flue gases (excess air, CO2, O2, and NOx) • Carbon Monoxide concentrations in the flue gases The three things we adjust that affect the combustion process are: fuel pressure, combustion air, and draft. Other factors can affect the combustion process, including impingement, excess air leaks into the heat exchanger, insufficient combustion air due to tight construction or improper ventilation, or an improperly installed venting system. If you perform combustion testing prior to and after a tune up, you can calculate Figure 7-7: Manual instruments Figure 7-8: Continuous sampling digital electronic instruments Chapter 7 Combustion


NORA Oilheat Technicians Manual
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