Gas Boiler


In case you aren’t aware, the little blue flame that constantly stays lit under your gas boiler is known as a “pilot light.” It gets its name from the days before matches were invented. Farmers or homeowners would keep a small flame burning so that they could quickly light a fire if necessary. This small name was known as a pilot.

The Gas Boiler Pilot Light

In a modern gas boiler, a small amount of gas is allowed to exit a small nozzle and is kept alight. Then, when heat is required, the pilot light will ignite the gas sent to the burners. It is imperative that the pilot light stay lit as gas will escape in any event.


Though there is only a small amount of gas escaping, it can build up over time. This buildup of gas can lead to an explosion or to suffocation. If your pilot goes out, you will most probably notice the sulfur smell of mercaptan, a product deliberately added to the normally odorless natural gas for just this purpose. If you smell gas in your home, the pilot light is one of the places that you should investigate as the source.

Lighting the Pilot

If, indeed, the gas boiler pilot light is out, it is a fairly simple process to relight it.

  1. First turn off the gas and allow the space to air out.There is a knob, usually red, located just above the pilot light for this purpose. Also notice that the knob can be depressed.
  2. Then, open some windows and wait 5-10 minutes. Once this is accomplished, the area will be safe to work in and you can proceed.
  3. Remove the plate covering the pilot light area. There are usually two tabs that you can turn with your fingers to gain access.
  4. Next turn the knob to the “Pilot” position.
  5. Light a match and hold it over the pilot light nozzle while simultaneously depressing the red button. Remove the match as soon as the pilot lights but continue depressing the knob for one minute. This clears any residual air out of the gas line.
  6. Lastly, if the pilot stays lit, turn the knob to the “On” position and you are done.

Lighting the pilot is an easy task for almost anyone just be sure that there is no smell of gas afterwards. If your really uncertain you can always call your local heating company to come to perform this task for you. Just keep in mind you should not pay more than their minimum service charge for this task.