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NORA Oilheat Technicians Manual

slot according to the firing rate requirements. The adjustable head operation is based on the relationship between what is called the “throttle ring” and the “flame retention ring.” The throttle ring is a ring at the end of the air tube that works in conjunction with the flame retention ring to create an air restriction and provide for the tertiary air effect. The adjustable head group allows the technician to move the head forward or backward in order to change the tertiary opening to accommodate different firing rate requirements, allowing fine-tuning of the burner. The fixed head is simple and easy to use; but remember that each head is only good for a specific range of firing rates. When you are installing a new burner or changing a firing rate to optimize performance, you must be sure you have installed the proper head for the specific firing rate. The variable head burner allows an infinite ability to fine-tune the burner for hard-tofire applications. With the wide variety of adjustments possible, you must be careful in picking the correct adjustments. Most variable head burners come with adjustment guides to help you set the head properly. Static pressure Static pressure is the means of producing and maintaining flow against resistance. Oilburners on the market today create much higher static pressures than units made in the 1980s and earlier. Some of these burners create such high static pressures that they can force the products of combustion through the heat exchanger and out of the building without the use of a chimney or power venter. See the section on direct venting in the Venting Chapter. (Chapter 6). High static pressure burners have been developed to accommodate the modern, flow resistive appliances (boilers, furnaces, and water heaters) and to assist with low or no draft conditions. A drop in static pressure can cause problems that range from delayed ignition, rumbles, and pulsation to the inability to adjust the burner for clean operation. The fan in a high static pressure burner starts with enough pressure to effectively push the products of combustion through the appliance without interruption. The higher static pressure also acts like a shock absorber or tightly wound spring to resist and absorb flame pulsations. This is especially needed in most modern appliances, which are designed with tighter, more efficient heat exchanger passages and increased draft drop that results in great heat absorption by the heat exchanger, and thus, greater efficiency. Chapter 1 Intro to Oil Burners 1-10 Introduction to Oil Burners


NORA Oilheat Technicians Manual
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