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NORA Oilheat Technicians Manual

facturer. The recommendations of the burner manufacturer should be followed whenever they are available. Electrode tips should never be permitted to touch or extend into the oil spray, because a carbon bridge will build up between them, ultimately causing ignition failure. Ceramic insulators should always be treated gently. They should never be dropped or packed loosely in service kits. In field servicing, they should always be wiped clean with a cloth, or cleaned with a solvent. If they show signs of aging or cracking, they should be replaced immediately. Ignition service problems Correcting faulty ignition is important. Delayed or faulty ignition is the prime cause of puffback. Puffback is the most disagreeable of all burner problems. It occurs when ignition is delayed. Due to some fault in the ignition system, the oil vapor does not ignite until after the burner has run for some time. Then the accumulated vapors all ignite at once, creating more combustion products than the venting system can handle. Delayed ignition can cause soot to blow out of the draft regulator, and in severe cases—called puff backs—it can knock down the flue pipe. Ignition problems are usually the easiest to recognize and solve. In most cases, we find it necessary to merely clean the electrodes and cables, and be certain that all connections are tight and that the spark gap is in proper adjustment. We must make certain that the electrode porcelains and the transformer terminal porcelain insulators are not crazed (small cracks on surface), cracked, or oil soaked. It is important that all exposed metallic components of the ignition system be a safe distance away from any other metallic part of the burner, since it is grounded. The shortest metal-to-metal distance throughout the entire ignition system should be that distance between the two electrode tips. Common sense tells us that any other arrangement would cause the spark to short out before the spark bridges the electrode tips. The best way to avoid this problem is to strictly adhere to the recommended electrode tip settings as shown in the manufacturer’s recommendations. Troubleshooting ignition problems 1. Connections at transformer junction box loose. Always check line voltage connections from the neutral wire of the primary control and the orange wire of the primary control (for intermittent ignition) and the ignition wire of the primary (interrupted ignition) to determine if there are loose connections at this Chapter 9 Ignition Systems Figure 9-13: Typical generic setting 5/32" Gap 5/16" Above Center 1/16" In Front of Nozzle Chapter 9—Ignition Systems 9-13


NORA Oilheat Technicians Manual
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