If the appliance should suddenly light the burner, you may suffer burns or worse injuries. Generally, thermocouples have no wire connections. Check the thermocouple for the correct depth of immersion. Both the bracket nut and the connection nut should be only a little tighter than if hand-tightened. Contact an appliance repair service to check the igniters. All information is subject to change at any time without notice. If you have gas-fired appliances such as a water heater, space heater, or cookstove, these appliances may have one or more thermocouples. A functioning thermocouple should also show a few millivolts DC when hot. [8] The tube connects to the gas valve below the pilot light. Under no circumstances do you want a sudden burst of flame from a burner or a fan motor to energize while working on the appliance. An old toothbrush is a perfect tool for this job. The thermocouple will sit so that the tip of the thermocouple is directly in the pilot lights flame. Working with response times. Thanks to all authors for creating a page that has been read 100,018 times. Better to be safe than sorry. A few simple maintenance steps could have your igniter up and running again quickly. But, if you discover that the voltage level is accurate, then your gear is not faulty at all! Sometimes you don't need to spend a single buck, and a little cleaning will do the trick for you. As mentioned before that this device will convert thermal energy to electrical energy. This guide reviews how to replace a thermocouple to ensure gas appliances stay in good working order, as well as how to relight a pilot light. 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. This article was co-authored by Gevorg Grigorian. You should hear a clicking sound as the igniter fires, and then the burner should light. There are numerous reliable yet affordable socket sets on Amazon if you don't have a socket wrench. If your equipment calls for a J type, you will need to replace with a J type. After that, generate heat on the thermocouple. Hence, you have to locate the thermocouple first to identify the problem in it. The thermocouple doesnt have wires. If the appliance has a thermocouple, the problem may be a faulty thermocouple. Pilot hood and flame direction. Make sure that the wiring is protected with insulation and is not damaged or broken anywhere in the circuit. Last Updated: October 25, 2022 Auto-igniters are quite simple. If the reading is less than 25 millimeters, it should be replaced. Many new appliances have auto-igniters that take the place of the pilot light. A quick look at Amazon and other places showed Id be waiting a couple of weeks for one to be delivered, so I decided to take a closer look at the thermocouple. Turn off the fireplace gas valve and remove the front panel from the fireplace. Video of the Day. Sometimes youll notice tour appliances arent lighting or lighting sporadically. Mine showed about 0.1 ohms when it wasn't working. Did you know you can get expert answers for this article? 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. Unhook Everything From the Gas Valve 03. If youre still unsure or dont have a working pilot light, test the thermocouple with a multimeter. Use it to try out great new products and services nationwide without paying full pricewine, food delivery, clothing and more. Finally, put back the thermocouple inside the box. By using our site, you agree to our. First, lose the connection of that copper tube. In our final section, we will conclude our discussion of repairing major appliances with a detailed examination of -- of course -- motors. 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. Lastly, observe the reading of the voltage meter. A thermocouple is a device that produces a small electric current when it is heated. As a small thank you, wed like to offer you a $30 gift card (valid at GoNift.com). To replace a thermocouple: Step 1: Unscrew the copper lead and the connection nut inside the threaded connection to the gas line. Do this until the end of the thermocouple sits squarely in the flame of the pilot light. Such as the gas heater, auto ignitor, and pilot light. If youre uncomfortable performing this test yourself, be sure to call a licensed HVAC contractor who can help you. Always double check to make certain that the thermocouple that you have in question is of the same match, style and calibration type for the application / equipment that you are using. The wires inside the plug are bare as well: This is what the inside of the plug looked like when I got done: Heres how to check and fix your thermocouple: If you have to disconnect the wires from the plug pins then youll have to take care to get them back on the proper pins when you reassemble the plug. Cleaning a thermocouple is not a fix for an issue, such as inaccurate readings. There are all sorts of methods out there. Look for a flexible tube plugged into the side of the thermostat. Then attach the other lead to the end of the thermocouple by the igniter. Normal business hours only. % of people told us that this article helped them. Answer: Unscrew the tilts switch wire. If the connections appear loose or corroded, then you will need to clean them and tighten them. Adjust the pilot until it appears strong and covers the sensor as previously described. 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. Others require that you push the gas valve in to open the valve to the pilot light. Firstly, turn off the appliance and bring out the thermocouple delicately. Ive been using the K-type thermocouple with my multimeter to measure the temperatures. A burned out or broken thermocouple should be replaced. All you need to do is scrape the thermocouple clean and then dry-wipe the residue. Sometimes the problem is simply that the thermocouple probe is too far from the flame. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); How to Fix a Thermocouple on a Water Heater? If the resistance measurement shows an open circuit, look closely at the thermocouple itself. What should I do if my thermocouple is coated with a white powder? This device is manufactured in a variety of styles, models, and technical specifications. Separate the thermocouple connector from the gas valve. You may have to wiggle it a bit before it comes loose. A few quick steps can have your gas appliance back in operation. Special Offer on Antivirus Software From HowStuffWorks and TotalAV Security. Now, remove the valve using pliers. If there is a safety or reset button, push the button, and keep it depressed. If youve been measuring the temperature of soldering iron tips like I was, you should also check and see if a splatter of solder is shorting the thermocouple. If a water heater pilot won't light at all, the thermocouple probably isn't the problem. Wipe away any remaining dirt or soot on the thermocouple with a clean, dry cloth. "Very clear and simple drawings make it easy to learn the basics in a short time. A working thermocouple will produce a reading of 25 to 30 millimeters. This instrument contains two probes; red and black. Turn off the fireplace gas valve and remove the front panel from the fireplace. Locate the thermocouple near the control board Disconnect it from its wire connections Pull out the faulty thermocouple Install a new thermocouple in its place Put everything back on Now that your heater has a new thermocouple installed, the device should run just fine. . Use a lighter or torch to hold a flame under this end. Since no flame is required to burn all the time, auto-igniters are less expensive to operate. Just the fact that you have to shut down and replace a thermocouple means lost revenue. You can test this yourself using a multimeter, but you may need a helper to keep the pilot flame burning while you do it. 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. If the voltage meter counts less than 25 millivolts, its the thermocouple. It should have a yellow tip and cover the tip of the thermocouple. Caution: Some older appliances may not have a safety device to turn the gas off when the pilot is extinguished. If the furnace still doesn't stay lit after cleaning, then its best to install a new thermocouple.Watch more furnace repairs: https://www.youtube.com/playlist?list=PLCo9SMjkdWBwU5dJaopTR09W7U05fEOF5___________________________00:00 Intro00:28 How it Works01:11 What You'll Need01:21 Identify the Thermocouple01:56 Cleaning03:16 Relighting04:13 Thermocouple Replacement___________________________AMRE Supply provides homeowners, service contractors, and property management with the parts and knowledge needed to get the best performance out of any property. You are looking for a few things. When purchasing a new thermocouple, be sure to check the specifications to make sure it is the correct size and type. The thermocouple on your appliance is with the pilot light. A dirty thermocouple may affect the ability of the gas fireplace to ignite. Therefore, its always wise to practice proper maintenance and upkeep of your appliances. The No. The plug fit better and held tighter, but still no temperature. Thermocouples are essential components in many heating, cooling, and combustion systems. Set your voltage meter to read voltage (V) in millivolts. Were committed to providing the world with free how-to resources, and even $1 helps us in our mission. Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place. Attach the red probe to the thermocouple and the black probe to the body of the gas valve. 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. 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. Once this check is done, turn the meter back to volts. 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. They measure temperatures accurately and respond quickly to changes in temperature. For that, turn on the gas valve and put it in the Light Pilot setting. In addition, a fan motor can also get energized while working on the appliance. When the flame is weak, boost up the flame to reach the device. Note: Only clean an orifice with compressed air as drill bits and other abrasive items can enlarge the opening. Here I repair a thermocouple for my DT304 digital temperature logger using a home made small wire welder.The small wire welder is a work in progress. To do this, youll need a voltmeter with a thermocouple probe. Level up your tech skills and stay ahead of the curve. You may have more pressing problems than a thermocouple in your gas-fired heater. You will need a wrench, multi-meter, and a flame source, like a candle or a lighter, to perform the test. drawings. 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. A thermocouple is a safety device that helps control the gas supply in gas-heated furnaces. This procedure is a bit more involved and requires a voltage meter. Expires 04/30/23 Cannot be combined with other offers. Learn about the Maintenance and Handling of Thermocouples, Email: 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. The clamp that holds the thermocouple may be hot. Therefore, inspecting and testing your thermocouple should be part of your furnace maintenance. Mosquitoes have a way of ruining an otherwise perfect evening. Close the fireplace access panel and restore the gas supply to the fireplace. The next step is to remove the thermocouple from the gas valve. Your thermopile voltage should be between 650mV and 800mV. Start the test by unscrewing the thermocouple from the gas valve. It might help to put a piece of heat shrink tubing over one of the wires before reassembling it. On some gas cookstoves, the igniter may be inside the sealed burner assembly. 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. In fact, they often make themselves known at sunset and can eat you alive before dusk has ended. Don't try to adjust the mechanism or tamper with the gas line. However, many people change them out about every four years. The thermocouple needs the full heat of the pilot light to create enough electrical current. It will secure your own safety. If the thermocouple isnt bad, then whats creating a problem? Push the connection nut to the threaded connection where the copper lead connects to the gas line. Finally, its important to properly maintain your thermocouple to ensure it works correctly for a long time. Five time constants are required for the sensor to approach 100% of the step change value. To replace a thermocouple: Step 1: Unscrew the copper lead and the connection nut inside the threaded connection to the gas line. 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. Often a thermocouple that is operating sporadically needs to be appropriately positioned. Save my name, email, and website in this browser for the next time I comment. Hopefully, you have understood how to find out the issue. Once this check is done, turn the meter back to volts. While putting it back together, I put a small piece of heat shrink tubing over one of the wires inside the plug. Unscrew the thermocouple from the gas valve and have a helper hold the gas control knob to keep the pilot burning. 1 millivolt is equal to 1/1000 of a volt. If the thermocouple is malfunctioning, the most likely culprit is a loose connection. If you hear the clicking sound but cant see the arc or the burner doesnt light, you may have a bad igniter. Turn the gas valve on the appliance to the Light Pilot setting. By creating an account you agree to the Hunker, How to Change a Thermocouple on a Fireplace, How to Troubleshoot an Electronic Ignition for a Superior Gas Fireplace, Adjusting the Gas-to-Air Ratio on a Heat-N-Glow Fireplace. If you find a dead short from pin to pin, check the inside of the plug and see if the wires are twisted. Your furnace pilot light should burn just fine if you have got all these steps right. 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