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NORA Oilheat Technicians Manual

electrode tips are permitted to operate while extending into the oil spray, it will promote a carbon bridge between the electrode tips, thus shorting out the spark and ultimately causing ignition failure. Clean the electrode tips and set them properly. 7. Electrodes too close to the nozzle. It has already been outlined that the electrodes set too close to the nozzle will promote spark shorting out from the electrode tip to the nozzle, thus creating a delayed ignition or ignition failure. Set electrode tips according to prescribed procedure. 8. Spark gap too wide. If the spark gap is too wide, either there will be no spark at all, or the spark will short out at some other point along the ignition system. Again, set tips as instructed previously. However, we are learning that in many applications today, and due to the changes in fuel oil, a slightly wider than normal gap may result in smoother ignition. Ignition of fuel is not an exact science and so a couple of settings may have to be tried to find the best results. 9. Insulators not held securely. In the event the electrode support bracket is loose, or the porcelains do not fit properly in the bracket, it is possible that the electrodes may move out of adjustment because of burner vibrations. Set electrodes and tighten the electrode support bracket securely, but do not overtighten because that may crack the ceramic insulators. 10. Puffbacks may be caused by lack of draft. If it is discovered that the ceramic insulators are heavily sooted and/or carbonized and the electrode tips are properly gapped and properly set, then it is Correcting faulty ignition is important. Delayed or faulty ignition is the prime cause of puffback. junction box. If they are loose, tighten them securely. Also check for loose connections at all terminals and make sure that wire nuts are tight. 2. Test the transformer. 9-14 Ignition Systems If the transformer is defective, replace it. 3. Loose connections at either the secondary terminals of the transformer, or loose connections where the high tension leads or buss bars are fastened to the electrodes. If these connections are found to be loose, attempt to tighten them. If this fails to solve the problem, replace the connectors. Also clean out any dust or dirt that may have accumulated in or around the secondary terminals of the transformer. As previously outlined, check the high voltage leads to determine if the insulation has become defective. 4. Remove the porcelain insulators from the electrode holder to determine whether they are cracked. In many cases the porcelains will crack beneath the clamp of the electrode holder. Replace cracked or crazed porcelains, even though they are still functioning properly. 5. Carbonized insulator. Carbon accumulations on the ceramic insulators will conduct electricity, thus causing the spark to short out against either the nozzle adapter, nozzle line, or the electrode holder. The carbon must be removed with a solvent or cleaner. Then the insulators must be dried and checked for cracks and/or spark leakage. The procedure for checking for spark leakage has been outlined. 6. Electrodes in oil spray. If the Chapter 9 Ignition Systems


NORA Oilheat Technicians Manual
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