Page 93

NORA Oilheat Technicians Manual

pattern. At this higher firing rate, spray patterns are not as critical. • Burners with firing rates above 3 GPH: Here it is advisable to standardize on solid nozzles which produce smoother ignition in most burners. Burners with hollow air patterns are the exception. Check the manufacturers’ recommendations. Nozzle brand interchange Replacing nozzles of one brand with those of another can sometimes present problems. There are subtle differences between manufacturers because they use different methods of production and evaluation. The burner manufacturers test their burners in different appliances and determine what type nozzle, from which nozzle manufacturer, works best in that particular application. Burner manufacturers publish nozzle recommendations called OEM Specification Guides. Be sure to have this information at hand. If you are working on a unit not listed in the Specification Guide, you will find that generally, all hollow nozzles have similar spray patterns and may be interchangeable. The variation shows up mainly in the solid nozzles, and if you must change brands, you will have to do some testing to determine the best nozzle for that application. Check with your supply house to secure a nozzle interchange chart to help you in your testing. Nozzle care and service suggestions Never, under any conditions, interchange the inner parts of a nozzle with those of another nozzle. Each nozzle component is matched exactly to all the other components of that nozzle. In fact, you should leave a nozzle in its original container until you install it. You should store all your nozzles in a proper nozzle box. They are available from the nozzle manufacturers. Handle nozzles carefully. Pick them up by the hex flats only. Do not touch the strainer or orifice. Even clean hands have enough dirt on them to plug up the tiny slots inside the nozzle. Obviously, you should never disassemble a nozzle you plan to use. Only install nozzles with clean tools to reduce the possibility of contamination. If possible, use a nozzle changer or nozzle wrench when changing a nozzle. Most open-end wrench handles are too long and increase the possibility of stripping the nozzle adapter threads. Before installing a new nozzle, flush out the nozzle line and adapter with clean oil, kerosene, or a solvent. Before you install the nozzle in the adapter, be sure the inside of the adapter is clean and free of carbon or contamination. Carefully examine the sealing surface of the adapter to be sure there are no scratches or nicks. These can be caused by careless handling, or just wear and tear. If it is scratched or nicked, then replace the adapter. Do not take a chance here. A leak between the nozzle and the adapter can cause serious problems. Do not put anything on the nozzle threads! Screw the nozzle into the adapter one-eighth to onequarter turn past hand tight (about 88 to 138 pounds of torque). The nozzle orifice face is polished to a mirror finish. Do not ruin it with a wire or pin, or by bumping it with a wrench. This will ruin the spray. If a nozzle is dirty, or plugged, change it. It is impossible to clean it out properly. It is tempting, especially in the middle of the night to try to clean out the orifice with a pin or tooth pick. It will not work. Replace it! A good quality nozzle should last at least two heating seasons. Contamination Chapter 5 Nozzles and Chambers Chapter 5—Nozzles and Combustion Chambers 5-9


NORA Oilheat Technicians Manual
To see the actual publication please follow the link above