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Why Does My Gas Boiler Pilot Light Keep Going Out?

July 05, 2023

Do you have a gas heating system? If so, you're probably familiar with a small blue light, a pilot light. Located in your boiler's combustion chamber, it lights the appliance's burner. If the pilot light goes out, you're left without heat. Typically, when the light goes out, it's due to one of the following reasons:

  • Bad Thermocouple
  • A Problem with the Pilot Assembly
  • Faulty or Damaged Gas Valve

In this blog, we'll take a closer look at these problems and give you all the knowledge you need when troubleshooting gas boiler issues.

Got a problem with your gas boiler pilot light?

Call Ranshaw Plumbing & Heating at (718) 767-0707 or schedule an appointment online today. Our techs have years of experience when it comes to gas boiler issues. In addition to handling the repair, we'll provide upfront pricing, convenient scheduling, and a 100% satisfaction guarantee.

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Bad Thermocouple

Your pilot light may not be igniting because of your boiler's thermocouple. Also known as a flame sensor, it consists of a copper rod located by the boiler's burner. It's designed to detect flames from the pilot light. The thermocouple will keep the gas line open if the pilot light is lit.

On the other hand, if it doesn't sense flames, the thermocouple will stop the supply of gas to the combustion chamber. This helps ensure your boiler operates safely by preventing dangerous gas levels from accumulating.

If the thermocouple is faulty, it might fail to detect a working pilot light. There are three main reasons why a thermocouple may stop working:

  • It's broken
  • It's dirty
  • It's not aligned properly next to the pilot light

When this happens, the thermocouple will shut off your gas, leaving you without heat. It's also important to note that your pilot light depends on gas to turn on. So, without gas flow, your pilot light will go out for good. Fortunately, a bad thermocouple can be cleaned (and, if necessary, replaced) during a simple gas boiler repair.

A Problem with the Pilot Assembly

Sometimes, extinguished pilot light is connected to an issue with your boiler. In other cases, the problem has to do with the assembly itself. The most common gas boiler pilot assembly issue is a dirty orifice.

The pilot light orifice consists of a small hole that regulates the gas flow. Ideally, the gas should flow freely through the orifice to ignite the pilot. However, if the pilot orifice is dirty, gas won't be able to flow through, and the light won't turn on. Generally, you can help prevent this problem from occurring by getting regular gas boiler maintenance.

Faulty or Damaged Gas Valve

A broken or faulty gas valve is the final possible cause of a gas boiler pilot light issue. Your boiler's gas valve delivers gas straight to the appliance's combustion chamber and pilot light. So, if the valve has a problem, your pilot light won't turn on. Here are some common signs of a damaged gas valve:

  • Boiler shutdown: A boiler shutdown is one possible indication of a damaged gas valve. If the boiler doesn't receive gas, it may stop working entirely.
  • Short cycling: If your boiler does not receive enough gas to reach the desired temperature, it might begin short cycling. This process involves the boiler repeatedly turning on and off.
  • Gas leak: A leak is the most serious consequence of a damaged gas valve. If you notice signs of a gas leak (such as a rotten egg smell or sudden dizziness), you should evacuate your home immediately and contact 911 and/or your gas utility provider.

Usually, a damaged gas valve cannot be resolved through repair. Rather, you'll have to get it replaced. Most gas valves can last up to 15 years, provided they're maintained regularly. Ranshaw Plumbing & Heating offers expert gas boiler repair, maintenance, and installation services. After examining your equipment, we can identify the issue and provide a solution. No matter the project, you can trust us to get the job done right the first time.

Need Help With Your Gas Boiler? Contact Ranshaw's Trained Technicians.

For over 60 years, our team has assisted local homeowners with all their boiler repair needs. Whether you have a dirty pilot light or a damaged gas valve, you can trust us to get to the root of the problem. Call us at (718) 767-0707 or schedule an appointment online today.

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