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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. If thermocouples start to give out unusual readings, it may be suffering from metal fatigue.
Why do I keep burning out thermocouples?
To burn out a new thermocouple in 1-2 weeks, the gas to your pilot would have to be set much too high and/or the position of the thermocouple would need to be very wrong, and even then I doubt it would fail so quickly. If you have doubts about what is wrong, your best bet may be to call a professional.
How long should a thermocouple last?
Thermocouples can last up to 10 years if properly installed and maintained, while furnaces can last 15-20 years, although either may wear out sooner in multifamily units.
Why does my thermocouple keep getting dirty?
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.
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.
How do thermocouples fail?
There are any number of ways a thermocouple can fail. It can short out, the sheath can fail, it can be damaged during operation or installation, it can be improperly installed, etc. The key is to perform a thorough root-cause analysis and prevent the failure again in the future, if possible.
What is the most common thermocouple failure mode?
The most common failure mode for thermocouples is for them to fail open, this is known as thermocouple burnout. Burnout can result from a variety of reasons including the thermocouple experiencing a temperature in excess of that for which it was designed, metal fatigue, and oxidation.
How long does a gas fire thermocouple last?
Although thermocouples can last several years, they don’t typically last as long as the furnace. It’s time to replace the thermocouple if the main furnace doesn’t stay lit. Most hardware and home improvement stores have replacements in stock.
Can a new thermocouple be bad?
If the thermocouple is working, you should be able to measure 30 to 40 millivolts of voltage at the connection end of the tube when the pilot flame is on. If the reading is less than 25 millivolts, the thermocouple is bad and needs to be replaced.
Can a thermocouple overheat?
A: Thermocouples are designed to be low maintenance items. If the back end of your thermocouple bulb gets constantly overheated, it will fail. With excessive back pressure coming from the burner ports, thermocouples can get burned up quickly.
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. Install a new thermocouple by screwing it in, heating it up a bit, and then lighting the pilot.
Can I replace a thermocouple myself?
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. Then detach the thermocouple from the burner and take it with you to the home center or hardware store to ensure you buy the right replacement.
How much does it cost to have a thermocouple replaced?
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.
How do you clean a thermocouple pilot light?
How to Clean a Pilot Light Cut off the gas to your furnace. Remove the pilot light and thermocouple assembly. Use your pliers or wrench to remove the pilot light and thermocouple from the bracket. Using the wire brush, brush away the carbon buildup and soot from both components.
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.
How do I stop the wind from blowing out my pilot light?
You can prevent a faulty pilot light from wind by fixing your thermocouple, gas release, protecting against downdrafts, capping your chimney, and checking your firebox cover.
Is a flame sensor and thermocouple the same thing?
People tend to use the terms “flame sensor” and “thermocouple” interchangeably. In truth, while they basically perform the same job, they’re not the same thing. If your furnace uses an electronic controller, it’s got a flame sensor. Thermocouples are used on standing pilot furnaces that have pilot lights.
How do you clean a thermocouple sensor?
The best way to clean your thermocouple is to use either a piece of steel wool or the coarse side of a sponge to gently clean off any soot or other remnants. You can use a pencil eraser to clean between the threads of the screw that connects the thermocouple to the control valve of your system.
How do I clean the thermocouple on my gas logs?
How to Clean the Thermocouple in a Gas Fireplace Turn off the fireplace gas valve and remove the front panel from the fireplace. Find the thermocouple, which is located next to the pilot light and looks like a small straight pipe. Use a can of compressed air to gently blow away any dust and dirt from the thermocouple.
How do you maintain a thermocouple?
A temperature indicator or recorder should be checked, either with a potential divider or a standard thermocouple at least once a month, whether it is used much or little. Terminals must be kept clean, insulation must be checked, and thermocouples themselves must be recalibrated.
