Understanding Your Oil Burner Ignition System


You depend on the burner in your furnace or boiler to get you through the harsh New England winter, so it’s a good idea to become familiar with how the ignition system works. That way you’ll know how to maintain and troubleshoot it … and when to contact us for assistance!


The ignition system in your oil burner ignites the fuel. Similar to a sparkplug, it uses high voltage generated by an ignition transformer to create a spark. The ignition transformer, which is a “step-up” transformer, draws a 120 volt current and steps that up to 10,000 volts. The other main component of the ignition system, the solid state ignitor, utilizes electronics to produce voltages of 14,000 to 20,000. Both the ignition transformer and solid state ignitor supply high voltage electricity to the electrodes, which are held in place by ceramic insulators. A spark jumps from one electrode to the other, creating an electrical arc that ignites the oil.


There are two types of ignition control systems: interrupted and intermittent.


  • Interrupted ignition – the ignition spark remains on briefly at the start of each operating cycle and, once the flame is established, turns off.
  • Intermittent ignition – the spark that ignites the oil vapors remains on the whole way (this was once called “constant ignition”).


Interrupted ignition is preferable, because intermittent ignition reduces the lifespan of the electrode and ignitor transformer. Plus, intermittent ignition increases electrical consumption and operating noise dramatically, and can even mask combustion problems.


The spark across the gap between the electrodes has to be strong enough to hold up to the velocity of air blown through the air tube by the burner fan. The ignition voltage also must be high enough to create a spark that ignites the oil.


The ignitor doesn’t usually require extensive maintenance, however, it’s important to keep it clean, as prolonged exposure to moisture can cause problems igniting. Wipe dirt and oil from every surface, check insulator bushings to ensure they’re clean and not cracked, and check that the electrode springs are clean and aligned perpendicular to the base of the ignitor. If your ignitor won’t ignite, or you’re looking for additional maintenance help, be sure to contact PayLessForOil.com; as a subsidiary of Fuel Services, we can connect you with reliable, certified technicians who will get your heating system back up and running, keeping you cozy through the New England Winter.

PayLessForOil provides a quick, professional service at an affordable price. I would recommend them to anyone.

- Andrew M. - South Hadley, MA