Pilot Light Goes Out When Burner Shuts Off [5 Reasons To Fix]

You have an old boiler or heater that has been serving you for a long time. But, recently, you had a problem with it- the pilot light goes out when burner shuts off. 

Regarding this, you change the thermocouple. But the problem remains. So, you go nuts and ask yourself- how can I fix the issue, and what causes the pilot light to go out when the burner also turns off? 

Dirty pilot burner, dirty gas line, and low gas pressure are some issues that cause the pilot light to go out if you shut the burner off. 

Below, we discussed those issues thoroughly and provided their solutions as well. So, let’s dive deeper into this guide. 

Pilot Light Goes Out When Burner Shuts Off [5 Reasons To Fix]

There are multiple reasons behind the water heater pilot going out after the burner shuts off. Below, we mentioned some reasons that cause the pilot light to go out when the burner turns off. So, let’s check them out.

01. Dirty Gas Line

Dirty Gas Line is the first reason you should check if the pilot light runs out when you shut down the burner. You know that natural gas is pretty dirty, and it could block the gas line. Consequently, the pilot light may go out. 

How to Fix:

Take a brush or scrubber and brush away the gas line thoroughly to suck away the dirt and dust. We hope it will solve the issue. 

02. The Puff Blows Out the Pilot Light

Heaters on this day use small pilot flames. Because of this, the pilot light blows away when the puff occurs created by the main burner. Indeed, some gas controls have pilot adjustments. So, when you shut the burner down, it creates a puff to blow out the pilot light. 

How to Fix:

The pilot light may keep blowing out due to the defective pilot out. To fix this issue, you must clean the pilot tube evenly. In this case, you can take a nail, straw, or other small objects to clean the dirt from the pilot tube. 

03. Dirty Pilot Burner

The pilot light may go out if the pilot burners get clogged up by dirt and debris.  Over time, dirt can build on and around the pilot burner, which causes the pilot light to go out.

How To Fix:

It would be best if you clean the unit every 2500 hours of operation. Besides cleaning the burner pilot, you should also clean the burner tube and burner assembly. 

To clean these parts, you can use compressed air, a vacuum cleaner, and a soft-bristle brush to keep the burner pilot free from dirt accumulation. Here is the step-by-step guide on cleaning the burner pilot:

  • Start with turning the burner off. Also, turn off the pilot. 
  • Check the burner as well as the pilot for dirt & dust.
  • Now, use the air compressor to blow air through the ports, holes, and slots of the burner and pilot. 
  • Don’t forget to clean the pilot assembly.

04. Gas Pressure Issue

Gas pressure issues, especially low gas pressure, will be the culprit behind turning the pilot light off. The pressure may reduce drastically if the gas tube or gas supply hose gets blocked by dirt, spiders, and debris. 

How to Fix:

A vacuum cleaner or an air compressor will be your best trait to release the block from the gas tube. First off, turn off the burner. Then, remove the pilot button and ignitor from the unit. Now, use the vacuum cleaner or air compressor to blow away the dirt and debris. 

05. Position Of Your Burner May Be Shifted

The change of the burner position may bring the burner too close to the pilot. Consequently, your burner may get too loose and when you turn it on, some of the gas may escape. 

It takes a couple of seconds for your burner to light as not enough gas reaches the pilot because of the leak. Due to this, extra gas will form a build-up around the burner. When the burner is lit, it may light up with a big whoos. Consequently, there may create enough force to blow out the pilot. 

How To Fix:

Re-positioning the burner to the right place will require a bit of mechanical knowledge. If you don’t have any experience regarding this, we recommend you hire a service guy to solve this issue for you. He will just re-position the burner and tighten it up to eliminate the leak. 

FAQs

Why does the pilot light on my furnace keep going out?

Due to a defective or broken thermocouple in your furnace, the pilot light may keep going out. To fix the issue, just replace the broken thermocouple with a new one. 

Do pilot lights stay lit on the gas fireplace when turned off?

Yes, pilot lights stay light on the gas fireplace when you turn it off with a knob. However, it may go out if you turn the gas fireplace off physically. 

Will a pilot light stay lit with a bad thermocouple?

No, a pilot light will never stay lit if its thermocouple gets defective. 

What are the signs of a bad thermocouple?

Discoloration on the tube, corroded wirings, and defective connectors are some of the signs of a bad thermocouple. 

How much does it cost to replace a thermocouple?

A new thermocouple will cost you around $20 bucks. However, if you replace the thermocouple professionally, it may cost you $150. 

What causes a thermocouple to fail?

Temperature changes may cause the metal of a thermocouple regular expansion and contraction. Due to this, the thermocouple gets weakened over time, resulting in a defective thermocouple. 

Conclusion

Now, you learned why the pilot light goes out when the burner shuts off. Dirty gas line, change of the burner position, dirty pilot burner are some reasons behind this issue. 

Just follow the guides we mentioned above to fix the problem. But remember, when your furnace pilot light lit but burners won’t ignite, it’s a different issue. If you face such an issue, you can read our simple solution guide with furnace pilot light lit but burners won’t ignite.

However, if the solution we provide today doesn’t work for you, then we recommend you get help from a certified HVAC guy to solve the issue for you.

Okay? 

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