It is positioned very close to the flame, and when lit, the pilot light tells the thermocouple to keep the gas line open. A thermocouple that is dirty or malfunctioning will often shut off your gas supply in error, causing the pilot light to go out and your furnace to stop working.
Why does the pilot light on my gas furnace 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.
How do you fix a pilot light that keeps going out?
Luckily, this is an easy problem to solve. All you have to do is shut off the gas, wait for everything to cool down and bend the thermocouple back into place. Voila! If the flame is directed through a dirty pilot opening, it will become unstable and appear wavy.
What would cause a pilot light to not stay lit?
The Buildup of Dirt or Debris Around The Pilot Light – Over the years it’s easy for dust, debris, and dirt to build up on the inside of the intake valve where the pilot light resides. This makes it difficult for the flame to breath and as a result causes the pilot light to go out suddenly.
How do you clean a thermocouple on a furnace?
Youtube quote:Use a soft abrasive pad or emery cloth to gently clean the outside of the thermocouple. Be careful not to scratch the coating. Next insert the thermocouple into the pilot assembly.
How much does it cost to replace a thermocouple?
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.
Why does my pilot light keep going out after replacing thermocouple?
If your water heater pilot won’t stay lit even after replacing the thermocouple, you most likely have a faulty gas control valve. It is a sign that the valve is failing to open and allow gas to flow to the pilot. You could also be dealing with a tripped or faulty thermal switch.
How much does it cost to replace a thermocouple on a furnace?
Thermocouple. If your furnace is an older model with a pilot light, it relies on a thermocouple to shut off its gas valve if the flame goes out. The average cost to repair or replace a thermocouple is $100–$250.
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 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.
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.
What do thermocouples do?
Thermocouples are sensors used to measure temperature. It is a device used inside a gas furnace in Kansas, to assist the pilot light in keeping your furnace running and safe. It works rather like a fail-safe to keep unburned gas from accumulating and burning, exploding or causing another type of health risk.
How do you test a thermocouple?
Youtube quote: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.
Why does my thermocouple keep going out?
Under constant exposure to a hot flame, a thermocouple wears down over time. Even a slight residue can make the thermocouple malfunction. The fix here is as easy as removing the thermocouple, cleaning it with a wire brush or something coarse (even an ordinary dollar bill works), and replacing.
What causes a thermocouple to fail?
A good thermocouple is going to be used, and that can lead to metal fatigue. Changes in temperature can cause regular expansion and contraction in metal, which will cause thermocouples to weaken over time. After enough time, metal fatigue can cause a thermocouple to break.
How do you bypass a thermocouple?
Youtube quote: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 long does a thermocouple last?
In effect, new thermocouples were installed into contaminated tubes, causing the degradation of the sensors and generating greater than a 100°F shift in accuracy. In this scenario, thermocouple life, which should have been close to one year, was shortened to within a week.
Does gas go through a thermocouple?
Because the thermocouple shuts off the gas supply when it doesn’t sense a flame, it prevents your furnace from receiving any gas when the pilot light is out.
