how to fix a bad thermocouple

The thermocouple can do this because, in its probe, it contains two different metals, and a voltage is generated when one of them is heated. Ive been using the K-type thermocouple with my multimeter to measure the temperatures. Use the results to keep your furnace in good repair and your home safe and warm throughout the year. Step 4: Under the bracket, screw the bracket nut over the tube. Check the following: 1. A correctly adjusted pilot flame is steady and blue, and stands between 1/4 and 1/2 inch high. But, how do you know if you have a bad thermocouple? It agrees to within a couple of degrees of the measured temperature on the soldering station when using the original tip so I figure the meter and the soldering station are at least somewhat accurately calibrated. While checking the tip temperature of the fine tip while soldering an SOIC-8 part, the meter just up and quit measuring temperatures. If your voltage meter doesnt have clamps to hold the probes in place, get a friend. How To Fix: Start with cleaning the thermocouple. How To Get Rid Of The Made In China Smell 7 Methods to Try! After three minutes, turn the valve to the PILOT position. Call Air Experts at919-480-2727or contact us online today to schedule furnace repair service! Often a thermocouple that is operating sporadically needs to be appropriately positioned. There are all sorts of methods out there. On other units, remove the panel that covers the pilot and gas burners. Mine showed about 0.1 ohms when it wasnt working. By signing up you are agreeing to receive emails according to our privacy policy. 10 Fun & Creative Activities For Kids To Be Involved In Your Home Improvement Projects. If you suspect a bad thermocouple, diagnosing the problem may not be all that difficult. Last Updated: October 25, 2022 Working with response times. If you find a dead short from pin to pin, check the inside of the plug and see if the wires are twisted. To do this, youll need a voltmeter with a thermocouple probe. Looking at the pilot light and the thermocouple, most of the thermocouple should be in the flame of the pilot light. The welded end of the thermocouple probe should protrude at least 1.5 inches (0.0381 meters) into the kiln chamber. Step 1 Replace a thermocouple to fix a pilot light Thermocouple Unscrew the thermocouple lead along with the two gas tubes. An exposed junction thermocouple offers the fastest response. No wonder that it is also used in the water heater. The pilot flame must be big and hot enough to heat the thermocouple to the temperature it needs to generate enough voltage to signal the gas valve. A damaged heater can turn on the gas oven automatically. (J, K, E, T, R, S, B, N). A few simple maintenance steps could have your igniter up and running again quickly. Turn On Gas Supply And Check for Leaks You should also turn the appliance off before working around the pilot light and burner. You might also get a splatter or crumb of solder or other metal between them. Sometimes the problem is simply that the thermocouple probe is too far from the flame. 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. That may not be a safe assumption, but I havent got anything else to go on. Learn about the Maintenance and Handling of Thermocouples, Email: Look around the igniter as well and make sure there is no build-up on the burner or near the igniter. Note: Only clean an orifice with compressed air as drill bits and other abrasive items can enlarge the opening. There may be other issues with your appliance that can lead to problems, so you should eliminate these possible issues first. Carefully remove the thermocouple from the gas valve by loosening the copper connector. If you suspect this is the problem instead of the thermocouple, call a professional. Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place. The actual thermocouple on mine is just a bare metal ball. If your furnace pilot light won't stay lit, then it might be an easy fix.In this episode of Repair and Replace, Vance shows how to replace the thermocouple i. Mine showed about 0.1 ohms when it wasn't working. 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/. drawings. This is the result of a phenomenon known as the Seebeck Effect. If the reading is less than 25 millivolts, the thermocouple is bad and needs to be replaced. When the flame is weak, boost up the flame to reach the device. Overtightening it can prevent the flame from lighting. The first step is to make sure that the appliance is off. In furnaces and water heaters, and in some ranges and dryers, the pilot light is accompanied by a safety device called a thermocouple -- a heat sensor that turns the gas off if the pilot flame is extinguished. Gevorg holds a BS in Business Administration and Management from California State University-Northridge. It is being used in a broad range of applications. It may have gotten crushed or one of the wires may have broken off. Fireplace How To: Testing A Thermopile - YouTube 0:00 / 3:28 Fireplace How To: Testing A Thermopile Fire-Parts 2.52K subscribers Subscribe 1.3K 266K views 6 years ago For technical support, or if. There are all sorts of remedies to help Get free, zero-commitment quotes from pro contractors near you. Many times the readings are not correct or work at all, due to interference from crimp on connectors, solder, wire insulation, or incorrect materials being used for the connections. Contact us for complete details. Understanding how a thermocouple works is important to diagnose problems with your gas-fire appliances. When the thermocouple is dirty, it won't produce enough voltage to open the gas valve, this will cause the pilot light to go out after you release the bypass button. Then delicately drag out the thermocouple. They will replace the thermocouple when they do this. Expires 04/30/23 *Available with approved credit. For a basic test, attempt to turn on the pilot light again. With it all reassembled, the meter was again showing the correct temperature. The thermocouple is a small electrical device, but it is a critical safety component on your furnace. Put Everything Back Into Its Place 07. As it heats up, attach one lead of the meter to one side of the thermocouple. Then attach a voltmeter between the thermocouple and the gas valve. Use a soft rag to wipe any residue from the igniter. 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. Your furnaces thermocouple is usually located right in the flame of the furnaces pilot light. Often the thermocouple connection points are overlooked, but are critical for proper readings. It's possible to replace the thermocouple without removing the burner assembly, and many repair people do this. Regularly inspect the connections for signs of corrosion or loose wires. Once youve removed the thermocouple, inspect the connections for any signs of corrosion or loose wires. An aged heater can create issues with gas valves, control panels, or even burners. If there is a safety or reset button, push the button, and keep it depressed. Unscrew the thermocouple from the gas valve and have a helper hold the gas control knob to keep the pilot burning. Then lets get your work done! References. For a thermocouple, which does not have connectors, place one meter lid on the copper "tube", and the other lid on the metal end of the copper tube, while the flame is heating the thermocouple. Be sure to inspect before you test, however, to ensure that there are no obvious problems that could affect the readings from testing! If the pilot lights but the flame goes out as soon as you release the button after holding it for 60 seconds, then the thermocouple is bad. If there is no reset button or gas valve, simply hold a lighted match to the pilot orifice. In any case, Ive been comparing the temperature at the tip of my new iron to the measured temperature on the display. Measure the resistance from pin to pin on the plug. Save my name, email, and website in this browser for the next time I comment. A burned out or broken thermocouple should be replaced. Light the pilot light and wait while you watch the voltage meter. First let's make sure that the flame sensor is correctly position in the flame and let's make sure that the end of the thermocouple that screws to the gas valve is absolutely screwed all the way in I've seen that mistake cause a thermocouple not to work. Now, remove the valve using pliers. Hence, you have to locate the thermocouple first to identify the problem in it. Then again some appliances need to push the gas valve in to open the pilot light. B) Remove and clean the pilot burner, pilot orifice, and tube. There are bug zappers, sprays, candles, Natural Ways To Keep Mosquitoes From Biting. If the thermocouple isnt bad, then whats creating a problem? customerservice@temprel.com. Does Citronella Actually Help Keep Bugs Away? Gas valves cannot be repaired. Your email address will not be published. Thus, find out the control of the gas valve and switch it off immediately. Use it to try out great new products and services nationwide without paying full pricewine, food delivery, clothing and more. Use an 8mm wrench to pull off the thermocouple. This device is manufactured in a variety of styles, models, and technical specifications. A functioning thermocouple should also show a few millivolts DC when hot. The information on this website is for informational purposes only; it is deemed accurate but not guaranteed. 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. If you have a K-type thermocouple that came with your multimeter or if you bought one of the many cheap K-type thermocouples from Amazon or wherever, it may some day quit on you. A good pilot light flame is blue. If it appears small and has an orange-yellow tinge, it may be too weak to heat the thermocouple. Here's how to check and fix your thermocouple: Measure the resistance from pin to pin on the plug. The job of the thermocouple is to keep the pilot lit. Like the other component parts in your furnace, the thermocouple can wear down over time, producing lower voltage than it should when heated. Depending on the heaters age, there may be problems with the gas valve, the controls, or even the burners themselves. If it is mashed or one of the wires is broken off right at the thermocouple then youre going to have get a new one - that kind of thing cant be fixed. The bare wires can get shorted just by bending them. Expires 04/30/23 Call for details. Push the connection nut to the threaded connection where the copper lead connects to the gas line. How to Remove the Thermocouple in a Heat & Glo Fireplace, Omega: Thermocouple: Different Types, What It Is, and How to Replace One, High Performance HVAC: How to Test a Thermocouple with a Multi-Meter. Then attach the other lead to the end of the thermocouple by the igniter. You may have to wiggle it a bit before it comes loose. Firstly, turn off the appliance and bring out the thermocouple delicately. Lastly, observe the reading of the voltage meter. I found that the display was fairly accurate with the original tip, but lost about 30 degrees celsius when using the fine tip I prefer. If your thermocouple is coated with a white, chalky material, this may indicate it's not functioning properly. Support wikiHow by Once you have located the thermocouple, do a visual inspection. Lastly, observe the reading of the voltage meter. Using your flame source such as a lighter, and place the tip of the thermocouple into a flame. Use a lighter or torch to hold a flame under this end. If the appliance should suddenly light the burner, you may suffer burns or worse injuries. If the reading is less than 25 millimeters, it should be replaced. It can result in overrunning your central heating pump. All information is subject to change at any time without notice. As a small thank you, wed like to offer you a $30 gift card (valid at GoNift.com). *Note: If you are inexperienced, wed recommend calling a licensed heating contractor to perform the test! Why Wont My Furnace Ignite? It might be broken, but theres a better than fair chance that it is just shorted out. If finding that the thermocouple does not read, the problem is most likely a bad connection, broken wiring, or open internally within the thermocouple probe circuit. Call for details. 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. Hopefully, you have understood how to find out the issue. Such as the gas heater, auto ignitor, and pilot light. 2. If you have gas-fired appliances such as a water heater, space heater, or cookstove, these appliances may have one or more thermocouples. This is a great option if you need help making the repairs or suspect your system has other problems, such as a faulty gas valve. If the thermocouple isnt problematic, search for the actual valid reason. The jack for the thermocouple on the meter was always a little flaky, so I thought it might be broken or just have bad contact. 0 seconds of 3 minutes, 6 secondsVolume 0%. I took the meter apart, disassembled the jack, tightened the pressure on the spring contacts, and reassembled the whole thing. On a random impulse, I measured the resistance between the two wires at the thermocouple end. If the connections appear loose or corroded, then you will need to clean them and tighten them. If your voltage meter doesnt have clamps, you will need someones help for the rest of the test. Multiple connections should be avoided in order to improve accuracy. A second set of hands is helpful for this step to keep the pilot burning. I can solder wires with the fine tip just fine at 260 degrees celsius, but it takes about 300 degrees to do SMD parts. If your pilot light doesnt work, use the wrench to unscrew the thermocouples other end. The idea is to make that sensor portion really hot. Experts suggest counting the voltage (v) in millivolts. 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. Your igniter may or may not have a pilot hole. Then again, a way too strong flame is also inaccurate. You can eliminate this possibility if there's enough room for you to reach in your hand and reposition the probe closer to the flame. To replace the thermocouple, youll need to purchase a new one that is compatible with your device. And the worst part is that you can have a bad thermocouple without even knowing. They can also get twisted and short out. The pilot light controls, reset buttons, gas valves, and thermocouple are usually contained in an assembly at the front of the furnace. Ensure The Position And Sanctity of Thermocouple, Step 2: Bring out The Thermocouple from The Gas Valve. 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. Just the fact that you have to shut down and replace a thermocouple means lost revenue. This article was co-authored by Gevorg Grigorian. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); How to Fix a Thermocouple on a Water Heater? I understand this seems quite confusing for you. You can check a thermocouple with a standard volt meter set to the Ohm's / Continuity function by checking across the positive and negative leads, in order to determine if the probe circuit is open or not. If you cannot see or detect problems proceedwith the test. "Very clear and simple drawings make it easy to learn the basics in a short time. Some panels have a screw on each side that needs to be removed and other panels lower on a hinge. Some panels have a screw on each side that needs to be removed and other panels lower on a hinge. Better to be safe than sorry. By using this service, some information may be shared with YouTube. 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. Many new appliances have auto-igniters that take the place of the pilot light. Here Ive shown a 5-step method to find out if your thermocouple is bad or not. % of people told us that this article helped them. Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place. Start the test by unscrewing the thermocouple from the gas valve. After that, generate heat on the thermocouple. Expert help is available online, over the phone or in person at one of the many locations across Canada.Connect with AMRE SupplyWebsite - https://www.amresupply.com/Facebook - https://www.facebook.com/amresupplyTwitter - https://twitter.com/amresupplyInstagram - https://www.instagram.com/amresupply The device can get dislocated while cleaning or other maintenance. Get free, zero-commitment quotes from pro contractors near you. But cleaning the device wont fix any technical issues. If the appliance has a thermocouple, the problem may be a faulty thermocouple. 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. This instrument contains two probes; red and black. The thermocouple doesnt have wires. Thermocouples are designed to detect a pilot light's loss of heat and close the gas valve to prevent a gas leak. If all heater zones show continuity then check the resistance of each zone and compare it to the value shown on your hot-runner. Light green color, on a type K thermocouple indicates the occurrence of aging and a change in the chemical composition known as Green rot. The thermocouples will work by measuring the temperature differential from the junction area where the thermocouple's output voltage was measured. Set your voltage meter to read voltage (V) in millivolts. Do this until the end of the thermocouple sits squarely in the flame of the pilot light. wikiHow is where trusted research and expert knowledge come together. Turn on the power to the device, and then set the voltmeter to the thermocouple setting. Start at the cable connector for the controller and work your way towards the tool. If there is no current from the thermocouple, the appliance will not let the gas valve open. Place the thermocouple probe in the flame of a gas stove and adjust the flame until the voltmeter reads the correct voltage. Finally, we will count the voltage level in the upcoming segment. Gevorg Grigorian is an Appliance Repair Specialist and the Owner of G and R Appliance Repair in Los Angeles, California. If a thermocouple tests at 25 millivolts or lower, it doesnt have the power to keep a pilot lit and it should be replaced. Performing a few simple inspections and maintenance may solve your thermocouple problem without the need to install a new thermocouple. Several things can cause the thermocouple to fail to operate properly. At the. Take the two leads from the meter and touch themthe meter should read zero. To gain access to the pilot burner, pull the door out of the furnace housing. Lets be apart from here. Most problems with this type of valve are due to thermocouple problems. I know this is the first question that hits your mind. Mostly, they are connected through a thin copper tube. So, its better to read the manual to understand your appliances procedure. When a thermocouple fails, the pilot light won't stay lighted. Your thermocouple voltage should be between 25mV and 30mV. However, if you need a professional to do the job, you can pay $120 to $150. It is often colored silver or red. Cannot be combined with other offers. The Red wire is generally the negative (-) wire in thermocouples, harnesses, and cables. 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. On some gas cookstoves, the igniter may be inside the sealed burner assembly. Remember to be safe when doing repairs around your home. 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. A working thermocouple will produce a reading of 25 to 30 millimeters. When a thermocouple fails in your control system, bad things happen. In our final section, we will conclude our discussion of repairing major appliances with a detailed examination of -- of course -- motors. It's a usually reliable device that works in conjunction with a standing pilot, which is the little flame that, like the Olympic torch, burns while the appliance is in operation. To operate correctly, a thermocouple requires the full heat from the pilot light. The wiring should also be inspected, as contamination on the surface of the wire can greatly reduce the accuracy of the temperature. Mosquitoes have a way of ruining an otherwise perfect evening. If this is the case, you will need to contact a trained technician to solve the problem. The auto-igniter then creates an electric arc to the burner, igniting the gas. Problems occur when the gas flow is obstructed or misdirected, or when the pilot is blown out. When it stops working, the furnaces pilot light also turns off. Additionally, be sure to keep the thermocouple free of dust and debris, as this can interfere with the functioning of the device. Sounds interesting? 1 millivolt is equal to 1/1000 of a volt. For the actual test, turn on your flame source, and place the tip of the thermocouple into the flame, leaving it there until it is quite hot. This procedure is a bit more involved and requires a voltage meter. By using our site, you agree to our. On some gas valves opening the pilot valve may require turning and holding the gas valve control to the left or right. Video of the Day. If your furnace pilot light won't stay lit, then it might be an easy fix.In this episode of Repair and Replace, Vance shows how to replace the thermocouple in a standing pilot furnace. Use the chart below to make sure that the positive and negative connections are in the proper order. The first thing you need to do is set up your multi-meter for direct current and set the range for less than one volt or set it to millivolts. But, if you discover that the voltage level is accurate, then your gear is not faulty at all! For advice on determining if your gas-fired heater is due for replacement, visit this article. Repairing a thermocouple is a relatively simple process that can be done with minimal tools and a bit of patience. If the igniter has a pilot hole, move a sewing needle carefully around inside the hole to loosen any trapped material. It should have a yellow tip and cover the tip of the thermocouple. Step 2: Hold a lighted match to the pilot orifice and turn the gas valve to the ON position. Then attach the black clamp to the gas valve. I understand this seems quite confusing for you. The proper place for the device is in the flame of the pilot light. To examine the gear, youll need a voltmeter. *** For Informational Purposes Only. The tube connects to the gas valve below the pilot light. If you buy through links on our site, we may earn a commission. Special Offer on Antivirus Software From HowStuffWorks and TotalAV Security. For that, turn on the gas valve and put it in the Light Pilot setting. Though you have cleaned the device with a soft hand. Replacing a thermocouple is a relatively easy fix that can take less than two hours. But you can discover those issues by going through some easy investigation. What should I do if my thermocouple is coated with a white powder? Take off the valve housing aside through a 133mm socket wrench. Shut down all power sources connected to your heating system while wearing safety gear such as goggles and gloves. Step 2: Locate your thermocouple. For more specific instructions on operating your multimeter, read the owners manual. Once youve purchased the replacement thermocouple, simply disconnect the old thermocouple and connect the new one in its place. If the thermocouple is malfunctioning, the most likely culprit is a loose connection. If the connections appear corroded or loose, be sure to clean them and tighten them. If youre uncomfortable performing this test yourself, be sure to call a licensed HVAC contractor who can help you. In that case, you have to replace a new thermocouple. The plug fit better and held tighter, but still no temperature. Question: Should thermocouples be in pilot flame? THERMOCOUPLE FUNDAMENTALS Service Life The desired voltage should be around 30 to 40 millivolts. Hunker may earn compensation through affiliate links in this story. A) Make sure the thermocouple is free of soot, centered in the flame of the pilot light, and is screwed in tightly to the control valve. To test the thermocouple, it must be hot. Your appliance may not have a pilot light or a thermocouple. There may be a broken wire in the plug if you find an open circuit from pin to pin. If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. An orange color from Iron Oxide on J and K types indicates internal moisture leakage. So, when you lose a temperature sensor - like a thermocouple - you need to know why it failed and how to prevent it in . Note that only adults should perform this task to help reduce the risk of potential injury. If you properly maintain your appliance and thermocouple, the thermocouple can last about 10 years. Compatible Thermocouple Calibration Type? You'll learn how a thermocouple works and how to clean the thermocouple.Buy a universal thermocouple online: https://www.amresupply.com/catalog/Thermocouples-Thermopiles-662364-HV1GIf your pilot light keeps going out, or if your burner won't stay lit, then its best to clean the thermocouple first when troubleshooting. The plug end was indeed shorted. . Contact an appliance repair service to check the igniters. {"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":"