How an Oil Burner Ignition System Works and How to Maintain It

The oil burner in your furnace or boiler is essential to its function. Its purpose is to ignite the oil, so it’s important to familiarize yourself with it. Here’s what you need to know:


Main Components

There are two primary components used for ignition systems – the ignition transformer and the solid state ignitor:


  • Ignition Transformer – This is a step-up transformer that “steps up” an incoming voltage of 120 volts to 10,000.
  • Solid State Ignitor – The solid state ignitor produces anywhere from 14,000-20,000 volts.


The electrodes receive high-voltage electricity from both components. From there, a spark “jumps” from the tip of one electrode to another, creating an electrical arc to ignite the fuel.


Ignition Systems

Oil burners use either interrupted or intermittent ignition systems. In an interrupted ignition system, the spark is active for a brief time at the start of the operating cycle, then turns off once there’s a flame. In an intermittent ignition system, the spark stays on while the burner runs.


Over time, interrupted ignition systems have proven superior because having the spark on throughout a cycle negatively impacts performance:


  • The useful life of the ignition transformer or solid state ignitor decreases
  • The useful life of the electrodes decreases
  • More electricity is used



Keeping the ignitor clean is key, especially to protect against moisture, which can prevent ignition. Be sure to periodically wipe each surface to remove moisture, oil and dirt. If for any reason your ignitor won’t light, contact Fsi Oil and Propane and we’ll send a highly-skilled technician over to take a look.