If the pilot light on your gas fireplace won’t stay lit, a very likely culprit is a component called a thermocouple. A thermocouple is a safety device and is a component of the ignition system. Its purpose is to not allow the gas valve to open if the pilot light isn’t lit.

Why does the flame on my gas fireplace keep going out?

Drip Loop: moisture in the gas line can cause a failure in the drip loop. This could be the reason why your fireplace won’t stay lit. Moisture can dilute the natural gas, so you’ll want to have a professional see if this is the problem at hand.

How do I know if my thermopile is bad?





We can test the voltage that the thermopile is giving off by using our Digital Multimeter.

  1. Time to Complete: 5 minutes.
  2. Recommended Tools.
  3. 1.) …
  4. When you turn the wall switch on, If your meter reads 0 or very low, you know you have a short in your thermopile and you should replace it.
  5. 2.)

How do you clean a thermocouple on a gas fireplace?

How to Clean a Thermocouple on a Gas Fireplace [3 Steps]

  1. Step 1: Leave the gas to cool first if it has been burning.
  2. Step 2: Polish the thermocouple.
  3. Step 3: Blow it out.
  4. Step 4: Light the gas.


How do I know if my thermocouple is bad on my gas fireplace?

Quote from the video:
Quote from Youtube video: Up next with your voltmeter probes in place light the pilot light and keep the knob depressed. Since your thermocouple is disconnected from the valve the pilot will not stay on unless you keep holding

Why does my gas fireplace keep going out and coming back on?





Bad Thermo Couple or Thermo Pile



A thermo couple is a sensor device that detects heat and permits the pilot light to stay lit. One of these devices could have gone bad or may have shorted out, causing your fireplace to turn shut down or turn back on at random.

What does it mean when your pilot light won’t stay lit?

If your pilot light won’t stay alight, it might be the thermocouple. Sometimes dust buildup collects on the thermocouple and blocks the sensor. Try cleaning the thermocouple and then relighting the pilot light. If it continues to go out, the thermocouple might need to be replaced.

Why does my gas fireplace shut off after 20 minutes?

If you get dust in the pilot assembly and the pilot needs to be cleaned out, it produces a “lazy” flame, which will be disturbed by the draught of the main burners. The flame lifts away from the thermocouple and causes the temperature on the tip of the thermocouple to drop. This, in turn, makes the gas valve shut off.

Will a pilot light stay lit with a bad thermocouple?

A thermocouple senses the heat of the pilot and allows gas to flow to the burner. A bad thermocouple will shut off gas to both the pilot and the burner so the pilot light won’t stay lit.

What does a thermopile do in a gas fireplace?



Thermopile is a an important device that converts thermal energy into electric energy. The purpose of a thermopile in a gas fireplace is to detect thermal radiation, for gas burner safety control.

How much does it cost to replace a thermocouple in a gas fireplace?

between $150 and $250

When replacing a thermocouple or thermopile with the help of a professional, you can expect to pay between $150 and $250.

How much does a thermocouple cost?



It costs $150 to $250 to replace a thermocouple. It checks to make sure the pilot light is on. It will shut the gas off if it’s not.

What are the symptoms of a bad thermocouple?

If you can’t get the flame to light at all, and you’re sure the gas is on, there’s probably an obstruction in the pilot tube. If the flame lights and goes out when you release the gas control knob after holding it in for the recommended 20 to 30 seconds, that’s the sign of a thermocouple malfunction.

How long does a thermocouple last on a gas fireplace?

ten years

The thermocouple usually lasts for ten years. However, if it malfunctions, the pilot will not light, and the fireplace will not operate. As a result, a thermocouple is a crucial component in the operation of a fireplace.

Does cleaning a thermocouple help?



Remove the thermocouple from the process assembly, using a steel wool or emery cloth, lightly clean the tip removing any build up. Cleaning a thermocouple is not a fix for an issue, such as inaccurate readings.

How do you bypass a thermocouple?

Quote from the video:
Quote from Youtube video: Okay that's the thermocouple here's a main igniter wire. And here is the tube that gives you propane. So you follow this wire down.

How do you troubleshoot a thermocouple?

Quote from the video:
Quote from Youtube video: Now just a triple check I will check the first lead that I first attached take it off the positive wire and then touch that across the sheets of the probe.

Can I fix a thermocouple?

Thermocouples are designed to detect a pilot light’s loss of heat and close the gas valve to prevent a gas leak. Replacing a thermocouple is a relatively easy fix that can take less than two hours.

How long does a thermocouple last?



All things considered, the question remains, “How long should my thermocouple last?” The answer to that question is that it depends on the application. In an ideal environment, that length of time can be indefinite.

How do I know which thermocouple to buy?

How to choose a Thermocouple

  1. Determine the application where you will use the thermocouple sensor. …
  2. Determine the temperature ranges the probe will be exposed to. …
  3. Determine how important a fast response time is. …
  4. Consider any chemical, abrasion or vibration resistance. …
  5. Consider any installation requirements.


Should thermocouple be in pilot flame?

The pilot flame should touch the thermocouple at a specific level. If the flame is blue and weak, and barely reaches the thermocouple, it needs to be stronger. If it extends well above the thermocouple, it’s too strong.