If you’re able to light the pilot light, but it goes out when you release the control knob, the thermocouple probably needs replacing. The thermocouple is a safety device that shuts off gas flow if it senses the pilot light is out, but when damaged it loses its regulatory ability.

What would cause a pilot light to keep going out?

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.

What do you do if your pilot light 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.

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.

Why does my hot water tank pilot light keep 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 on my gas fireplace?

The Fix: Pilot Light to Gas Fireplace Won’t Stay Lit



This can be an indication that your fireplace thermocouple is either bad or worn out. However, if your pilot is lit but the gas fireplace isn’t, then there’s probably a problem with your thermopile.

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.

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.

How much does it cost to replace a thermocouple?

1 cause of pilot lights that won’t stay lit is a worn-out thermocouple. It’s easy to replace and a new one costs $5 to $10. Rather than trying to unfasten the thermocouple inside the water heater’s burning chamber, it’s easier to remove the whole burner and thermocouple assembly.

How do I know if my thermocouple is bad on my furnace?

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.

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.

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 should a thermocouple 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.

How do you test a thermocouple?



Quote from the video:
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.

What makes a thermocouple go bad?

Soot buildup on the thermocouple may block the flame. Under constant exposure to a hot flame, a thermocouple wears down over time. Even a slight residue can make the thermocouple malfunction.

How do you fix a thermocouple?

Quote from the video:
Quote from Youtube video: So now we just take the thermocouple. And we push it into the bracket. And we push it into that compression fitting. And we're going to slide it down and in this case.

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.

Can you adjust pilot light flame?



Adjusting the Pilot Flame



If the pilot flame is too small, you may be able to make it larger by turning the pilot adjustment screw on the valve control counterclockwise with a screwdriver to open it.

What color should pilot flame be?

bright blue color

Inspecting a Gas Furnace Pilot Light Flame



A natural gas flame should be a bright blue color with a small amount of yellow at the very tip. A propane flame will have more of a bluish-green flame with a tinge of yellow at the tip. The flame should strong enough to cover about 1/2 inch at the end of the thermocouple tip.