Reasons Why the Boiler Pilot Light Won’t Stay Lit


Like many other types of heating systems, boilers require a lit pilot light to ignite the burners, which in turn power the system to produce heat. The pilot light is like the Olympic flame that stays lit throughout the tournament in celebration of the games – except that it burns 24 hours a day all year long to keep the boiler working. It may not carry the symbolism of the Greek god Zeus or represent the endeavor for victory like the Olympic flame, but it does help keep the house warm throughout cold weather conditions. So, when the flame goes out and won’t seem to stay lit or turn back on, it poses a major issue for the household.

Because boilers are complex systems that operate using highly-pressurized boiled or steamed water to evenly heat the dwelling, we do not recommend that you try to assess the pilot light issue on your own, as it can be a very dangerous task. Always consult with your local boiler services company in Bucks County, PA, such as us at Ivey Air, about your boiler system and let them handle the job.

However, to understand why your boiler’s pilot light won’t stay lit, here are some reasons that could be causing the problem.

The Thermocouple is Filthy, Bent or Damaged

If you were examining the pilot light in your boiler, you might have noticed a long metal wire traveling from the gas valve to the area where the pilot light flame would be. This piece of metal is called the thermocouple and it acts as a heat sensor that responds to the pilot light flame to create an electrical current that keeps the gas valve open. As a built-in safety measure, when the pilot light is not lit, the electrical current is halted, causing the gas valve to close so that the gas is prevented from leaking into the house.

When the thermocouple is faulty, the gas valve can no longer stay open, which cuts off the fuel supply to the pilot light, causing it to smother out. If the thermocouple is extremely dirty at the tip, bent away from the flame or damaged, it could be the diagnosis of why the boiler isn’t working. If this is the case, the thermocouple needs to be replaced or repaired.

The Pilot Tube is Dirty

Connected to the pilot light assembly is a tube where the gas flows to ignite the flame. One possibility of the flame’s inability to stay lit is that the tube is blocked with dirt. To fix it, the pilot light tube needs to be cleaned out.

Kettling Has occurred in the Heat Exchanger

Over time, the heat exchanger in the boiler can become blocked due to mineral deposits that build up from the flow of mineral-rich water – also known as “hard water.” Once the heat exchanger becomes blocked, the boiler system will shut itself down to prevent dangerous water pressure levels from building up – also another built-in safety precaution.

Having any part of the boiler malfunction can be a frustrating experience because it causes the atmosphere of your home to quickly become uncomfortable. As the HVAC experts, we can get to the bottom of why your pilot light won’t stay lit, whether it be a replacement, repair or emergency service. Don’t put you or your family’s health at risk by trying to diagnose the pilot light on your own. Call us at 215-695-4170.

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