Maybe itll help, maybe it wont. Generally, thermocouples have no wire connections. Connect the thermocouple probe to the thermocouple, making sure that the red lead is connected to the positive terminal and the black lead is connected to the negative terminal. Light green color, on a type K thermocouple indicates the occurrence of aging and a change in the chemical composition known as Green rot. With it all reassembled, the meter was again showing the correct temperature. You might also get a splatter or crumb of solder or other metal between them. The thermocouple has two dissimilar metals that form an electrical circuit. Your furnaces thermocouple is usually located right in the flame of the furnaces pilot light. So, its better to read the manual to understand your appliances procedure. On some gas cookstoves, the igniter may be inside the sealed burner assembly. You will need a wrench, multi-meter, and a flame source, like a candle or a lighter, to perform the test. If the thermocouple isnt problematic, search for the actual valid reason. Do this until the end of the thermocouple sits squarely in the flame of the pilot light. Then again, a way too strong flame is also inaccurate. It does not constitute professional advice. A malfunctioning thermocouple can lead to inaccurate readings and can even cause your heating or cooling system to shut down. Replace the furnace access cover and test the furnace operation by changing the thermostat settings to make sure the furnace turns on and off properly. The idea is to make that sensor portion really hot. Normal business hours only. Sometimes the sporadic movement of the thermocouple can also shake its position. A working thermocouple will produce a reading of 25 to 30 millimeters. With any gas-fired appliance, if a strong smell of gas is present, do not try to relight the pilot or turn the appliance on, or turn any lights on or off. Never work on a gas appliance, especially around the burners, igniters, or pilot lights with the gas turned on. Multiple connections should be avoided in order to improve accuracy. If the thermocouple wiring is bare, missing insulation and is touch together anywhere between the sensing - probe end, and the connection points, the thermocouple will read at the area where the bare wiring is touching together. Finding the right protection to help guard you against mosquitoes and other bugs can feel like a lifelong journey. Once I got all the fuzz from the cloth covered wires out of the way, I could see that the bare wires inside had been twisted around and shorted out. How To Replace Thermocouple On Ge Water Heater, Your email address will not be published. Therefore, inspecting and testing your thermocouple should be part of your furnace maintenance. Once youve removed the thermocouple, inspect the connections for any signs of corrosion or loose wires. It is often colored silver or red. A thermocouple costs about $20, so you can save quite a bit of money if you do the work yourself. Yes, you can clean a thermocouple, but the task must be done with a light touch. The thermocouple needs the full heat of the pilot light to create enough electrical current. Call Air Experts at919-480-2727or contact us online today to schedule furnace repair service! Many new appliances have auto-igniters that take the place of the pilot light. Nothing lasts forever, and when the thermocouple wears out, the pilot won't stay lit and your appliance won't work. Your email address will not be published. Your igniter may or may not have a pilot hole. You can also eliminate obstructions in the pilot tube as a possible cause by turning off the gas, unscrewing the pilot tube from the gas valve and blowing compressed air from a can through the tube. You should hear a clicking sound as the igniter fires, and then the burner should light. To replace a thermocouple: Step 1: Unscrew the copper lead and the connection nut inside the threaded connection to the gas line. Just swap the two wires and itll be OK. A little poking around saved me a few bucks and a couple of weeks worth of waiting for a new thermocouple. In most cases, the thermocouple attaches to the gas valve with a thin. Wait until your thermocouple properly generates heat. Theres about three ohms of resistance across the thermocouple at that end. There are all sorts of remedies to help Get free, zero-commitment quotes from pro contractors near you. The bare wires can get shorted just by bending them. Thank you.". The pilot should heat the top 7/8" of the thermocouple with a clean (blue) flame. Carefully complete a thorough inspection of the thermocouple probe looking for any pin holes, cracks, and areas with discoloration indicating internal contamination issues. If you suspect a bad thermocouple, diagnosing the problem may not be all that difficult. No wonder that it is also used in the water heater. The thermocouple on a gas fireplace may eventually become clogged with dirt and soot, which can reduce the effectiveness of the thermocouple and may eventually prevent the fireplace from lighting as expected. Were committed to providing the world with free how-to resources, and even $1 helps us in our mission. This is what a cheap K-type thermocouple looks like: Note that the wires to the thermocouple (the little metal ball at the end of the cable there in the upper left corner of the picture) are bare - they can easily be shorted by bending or twisting the wires. Lastly, observe the reading of the voltage meter. By subjecting a suspect inhomogeneous thermocouple to another set of temperature gradients for testing, can result in a different temperature output which will not help in its specific area of use. Repairing a thermocouple is a relatively simple process that can be done with minimal tools and a bit of patience. The following are the six most common causes of thermocouple measuring errors, followed by ways to rectify them: 1. Measure the resistance from pin to pin on the plug. Next, use a multimeter to check for continuity of the heater zones. Lets be apart from here. Several things can cause the thermocouple to fail to operate properly. Take the two leads from the meter and touch themthe meter should read zero. How to Survive an Encounter with an Ostrich, Unlock expert answers by supporting wikiHow, https://www.familyhandyman.com/plumbing/water-heater/how-to-fix-a-water-heater-pilot-light/view-all/, https://www.bobvila.com/articles/furnace-troubleshooting-2/, https://www.familyhandyman.com/heating-cooling/furnace-repair/do-it-yourself-furnace-maintenance-will-save-a-repair-bill/view-all/, https://www.familyhandyman.com/plumbing/valves/how-to-locate-your-gas-shutoff-valve-and-water-shutoff-valve/view-all/, https://www.familyhandyman.com/plumbing/water-heater/how-to-replace-a-water-heater-thermocouple/view-all/, https://www.sensorsmag.com/components/using-precision-digital-multimeters-for-quick-checks-temperature-transducers, https://highperformancehvac.com/how-test-thermocouple-multi-meter/, https://heatinghelp.com/systems-help-center/thermocouple-testing-procedure/. Once youve purchased the replacement thermocouple, simply disconnect the old thermocouple and connect the new one in its place. The information on this website is for informational purposes only; it is deemed accurate but not guaranteed. wikiHow is where trusted research and expert knowledge come together. On some gas valves opening the pilot valve may require turning and holding the gas valve control to the left or right. Pull the valve housing aside using your 13mm socket wrench. Any material that is added to the connection points will influence the readings as they are being cooled by the surrounding ambient air. Whatever you do, never use any cleaning products or liquid of any kind. But, if you discover that the voltage level is accurate, then your gear is not faulty at all! For a basic test, attempt to turn on the pilot light again. If you buy through links on our site, we may earn a commission. If your thermocouple is coated with a white, chalky material, this may indicate it's not functioning properly. Make sure that the wiring is protected with insulation and is not damaged or broken anywhere in the circuit. While buying the voltmeter, try to get one with the clamps. By using this service, some information may be shared with YouTube. To examine the gear, youll need a voltmeter. FIND LOCAL CONTRACTORS. Don't try to adjust the mechanism or tamper with the gas line. I can solder wires with the fine tip just fine at 260 degrees celsius, but it takes about 300 degrees to do SMD parts. This instrument contains two probes; red and black. Older gas appliances may have pilot lights that provide instant ignition when the gas is turned on. Make sure the connection is clean and dry. drawings. Appliance Repair Expert. It should be low, but definitely not a dead short. As a small thank you, wed like to offer you a $30 gift card (valid at GoNift.com). The auto-igniter then creates an electric arc to the burner, igniting the gas. To gain access to the pilot burner, pull the door out of the furnace housing. It is usually found near the system's pilot lights or burners. Stocking the largest selection of appliance parts, heating, plumbing, lighting, and janitorial supplies, AMRE ships almost anywhere in Canada within 24 - 48 hours. Save my name, email, and website in this browser for the next time I comment. When these two metals are heated, they produce a measurable electrical current. Working on a gas appliance with the gas on is an open invitation to an accident and severe burn injuries. Just using the probe had twisted the wires around inside the strain relief and shorted them. How Does a Gas Water Heater Thermocouple Work? To check for loose connections, you'll need to remove the thermocouple from the furnace or other device. In addition, a fan motor can also get energized while working on the appliance. The pilot can go out for a number of other reasons, however, so if you're having trouble getting the pilot to stay lit, the thermocouple may not be at fault. Shut Off The Gas Supply 02. Use any type of steel wool or emery cloth to wipe off any dirt. If you suspect that you have a defective thermocouple, the best way to evaluate a used thermocouple is to place a new, or known good thermocouple adjacent to the suspect one in order to compare and document readings between both. Locate the thermocouple on the gas control thermostat. The main reason for the decalibration is that the wires can become chemically attacked, which effects the wire composition, mechanical properties of the material and ultimately the temperature readings. Reading the voltage level is the last step to find out the real cause. If the flame goes out repeatedly, it may be getting too little air; if it's yellow at the tip, it's getting too much air. Include your email address to get a message when this question is answered. Then attach a voltmeter between the thermocouple and the gas valve. A yellow or orange flame means the system needs to be cleaned. Like the other component parts in your furnace, the thermocouple can wear down over time, producing lower voltage than it should when heated. If it appears small and has an orange-yellow tinge, it may be too weak to heat the thermocouple. 2 Next, attach the leads from the multi-meter to the thermocouple: put one on the side of the thermocouple, and attach the other lead at the end of the thermocouple that sits in the pilot light. If the thermocouple isnt bad, then whats creating a problem? The plug fit better and held tighter, but still no temperature. Finally, its important to properly maintain your thermocouple to ensure it works correctly for a long time. *** For Informational Purposes Only. The job of the thermocouple is to keep the pilot lit. Use a lighter or torch to hold a flame under this end. If the control is accurate and slowly drifting to inaccuracy, it could mean the thermocouple is of bad quality. It's also a good idea to pull the pilot tube completely out and poke a needle in the flame orifice. Learn about the Maintenance and Handling of Thermocouples, Email: Cleaning the thermocouple is a pretty simple process but should only be done when the fireplace is turned off and is completely cool. Ive been using the K-type thermocouple with my multimeter to measure the temperatures. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/0\/04\/Test-a-Thermocouple-Step-1.jpg\/v4-460px-Test-a-Thermocouple-Step-1.jpg","bigUrl":"\/images\/thumb\/0\/04\/Test-a-Thermocouple-Step-1.jpg\/aid9649384-v4-728px-Test-a-Thermocouple-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"