A faulty, misaligned, dirty, or damaged thermocouple is often the culprit behind your pilot light going out. The thermocouple is an automatic safety shutoff device that prevents the gas valve from opening if the pilot light is out.

How do you fix a pilot light that won’t stay lit?

Check the Thermocouple



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.

What does it mean when your water heater pilot light keeps going out?





Thermocouple Issues



If it senses that your water heater pilot light keeps going out, the thermocouple will shift off the gas supply to the heater. Over time, thermocouples can malfunction, accumulate dust buildup, or the device can get bent away from the pilot light’s flame.

Why does my pilot light keep going out with a new thermocouple?

A furnace pilot light won’t stay lit after replacing the thermocouple because the pilot burner is unclean or the gas valve has a bad magnet. It’s recommended to clean the pilot burner using a wide bristled brush to remove debris. If the gas valve has gone, it’s best to call a specialist to replace the gas valve.

How much does it cost to replace a thermocouple on a furnace?

$150 to $250

Replacing a thermocouple costs $150 to $250, mostly due to labor time. On older models without an ignitor, it checks to make sure your pilot light is lit. If it’s not, it’ll shut the gas off.

Can you clean a thermocouple?





Yes, you can clean a thermocouple, but the task must be done with a light touch. 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 test a thermocouple?


Quote from Youtube video: If I take my wire and attach it to anywhere along the sheets of the probe. I attached to the sheath and I'm getting continuity this is a grounded thermocouple if this was an ungrounded thermocouple.

Does gas leak if pilot light goes out?

If the pilot light goes out on a storage or instantaneous hot water heater, space heater or a ducted heater, you will not have a gas leak. This is because all modern gas appliances with pilot lights have a fail-safe device that closes off the gas to the appliance in the case when the pilot may go out.

Can I replace a thermocouple myself?

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 often do thermocouples need to be replaced?



The fireplace has thermocouples and switches. The thermocouples should last for a long time. According to experts, a four-year check cycle is all that is needed.

Why does my furnace flame keep going out?

If your furnace keeps shutting off, it could be due to low airflow. There are several indirect issues that cause low airflow. Dirty Air Filters. If you don’t change your air filters often enough, the filters will become dirty and clogged, which means the heat exchanger retains heat and eventually causes it to overheat.

Why does my furnace keep shutting off after a few seconds?

A common reason a furnace short cycles is because the heat exchanger, the part that heats your air, is getting too hot due to a lack of airflow. Once the heat exchanger overheats, it trips the high limit switch, which shuts the furnace down to protect it.

How do I stop my furnace from short cycling?



Quote from the video:
Quote from Youtube video: So to fix this issue shut off your thermostat. And open up the furnace. And then replace the batteries on the thermostat.

Why does my furnace turn on and off repeatedly?

When a furnace keeps turning on and off, it is usually due to short cycling. This is the term used to describe problems originating from within the heating system. If short cycling is not promptly diagnosed and corrected, it could cause permanent damage to your heating unit and higher utility bills.

Why does my furnace run for 5 minutes then shuts off?

If your furnace turns off after a few minutes, there is a good chance it is caused by a faulty or dirty flame sensor. This vital component is designed to keep an eye on the gas burner. When it cannot sense that burner, the furnace runs then shuts off and starts again. This could be a relatively easy fix.

How do you clean an ignition sensor?

Clean the Sensor



Once you have removed the sensor, gently rub the metal rod (and nothing else) with a very light grit sandpaper. Remember, you’re not sanding down an auto body here, just ridding the sensor of any buildup. Then, use a clean paper towel to wipe clean any dust left behind by the sanding.

How do you trick a flame sensor?



Luckily, making such a check is very easy:

  1. Take a multimeter with microamps (µA) measuring system.
  2. Keep the furnace system turned on.
  3. Connect it to the wire that is leading to the gas valve.
  4. Connect the other side of the multimeter to the sensor terminal.
  5. Take the lead away from the flame sensor.