how to trick a thermocouple

Never use anything abrasive to do so as you could damage the thermopile or thermocouple. There are 15 references cited in this article, which can be found at the bottom of the page. But there is … Replacing it is a relatively simple job that you can accomplish with a wrench. At this point I advise you to call in a professional to check things out. Thanks for the info. This rod is connected to your furnace’s gas valve. Plumbers and HVAC service companies are skilled and knowledgeable with standing pilot gas systems. Secondly, turn on the meter and set it to Ohms. An oven thermocouple is seldomly found on modern ovens. The working principle of thermocouple is based on three effects, discovered by Seebeck, Peltier and Thomson. Replace the valve. The TC junction should be prepared by stripping a bit so … Thanks for proof reading and ensuring all our articles are idiot proof. Another solution is to use a transmitter. As an update, cold weather set in yesterday, I have been using the gas log fireplace more often, and running it hotter, than usual and since cleaning the pilot has begun to stay on more reliably. In the early 1900s, Honeywell applied it to the safety gas valve. One thermowell accommodates multiple thermocouple elements within the insulation inside a common stainless steel sheath. Altitude and gas value affect it. When the pilot is on, the fireplace turns on readily when I flip the wall switch. Next, ensuring the tip is nice and hot from the flame, take one lead from the meter and put it on the shaft of the thermocouple and the other lead and put on the end of the thermocouple where it makes contact with the gas valve. Replace the Thermocouple. A thermocouple is an electronic temperature sensor which uses two different metals joined together in a protective outer sheath. A standing pilot gas valve has two inner valves, one for the pilot light and one for the main valve. Importantly, always make sure the tip of the thermocouple is directly in the pilot flame. The fireplace did, however, shut itself off (pilot stayed on) once. This planet needs more geniuses like you around. Don’t you. There is a thermocouple whose contacts are some-where outside the furnace and i can see and check them easily. ODS is an oxygen depletion sensor. They are cheap enough. I have an un-vented gas fireplace. Any thoughts? Connect the crocodile clips to the slots in the multimeter. You ask a friend, and the friend tells you the thermocouple is bad. With over 13 years of experience, Gevorg specializes in residential and commercial appliance repairs as well as heating, ventilation, and air conditioning (HVAC) services. Be cautious when reinstalling the thermocouple. The thermocouple, which operates as a safety device, turns the gas supply off when the pilot light goes out. The push button must be depressed through the whole check. You will need a multimeter that will read millivolts (most meters read small voltage like millivolts, which is 1/1000th of a volt) and a source of fire such as a lighter or small torch. You are a freaking jerk. The thermocouple on your gas fireplace is a heat-sensitive device that keeps the pilot gas tube open while the pilot is lit. The thermocouple lasts for 10 years or more, and when it fails, the pilot won't stay lit and the fireplace won't work. 30 July 2020. 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/, consider supporting our work with a contribution to wikiHow. Your email address will not be published. You know you have gas, and everything seems to be fine so what is the problem? Finally, Good luck! Since I cannot locate a thermocouple that looks like the one on this assembly, I would have to modify the bracket so that it might receive an ‘aftermarket’ thermocouple. Hi. Necessary cookies are absolutely essential for the website to function properly. So, back to the drawing board on making adjustments for altitude. This end appears needle-shaped and is designed to take on heat, so put the tip into the flame. How to Test a Thermocouple with a Multi-Meter step by step: Thermocouple fits securely in the pilot burner (pictured above). From the extension cables that could serve as antenna to pick up stray voltages, to ground loop problems, to advanced signal conditioning modules applied to curb noise and composition challenges in the thermocouple material, it does not appear to be a simple device in the real sense. If your thermocouple is coated with a white, chalky material, this may indicate it's not functioning properly. Once the thermocouple is sealed against the O-Ring, the probe will no longer move up and down. With your other hand, twist the two bare sections of wire together for 3–4 turns. Manufacturers/Contractors derate gas appliances in elevations over 2000 feet. If the tip is in the flame, you have held the nob on the gas valve down for longer than a minute, the pilot flame is strong and steady, and the pilot still does not stay lit, then you likely have a problem with the gas valve. When a thermocouple … We also use third-party cookies that help us analyze and understand how you use this website. This commission helps us pay for the overhead of running this website. "Very clear and simple drawings make it easy to learn the basics in a short time. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. You need a new gas valve. Is there any method to check this thermocouple with Digital |Multi Meter ? Gevorg Grigorian is an Appliance Repair Specialist and the Owner of G and R Appliance Repair in Los Angeles, California. If you haven’t done so make sure to test it as instructed on this page. This is a sort of “trick” step. Additionally, gas companies may add additional gases. A thermocouple is a sensor for measuring temperature. It is likely a thermopile although there are some ventless gas logs that use thermocouples also. By using this service, some information may be shared with YouTube. With the thermocouple being disconnected from the gas valve for checks, the pilot valve should not stay open and the flame should go out when the push button is let up. That is simply a test to check the meter for continuity. by High Performance HVAC | Gas Furnaces | 15 comments. The thermocouple is a small electrical device, but it is a critical safety component on your furnace. The tube connects to the gas valve below the pilot light. The thermocouple responds to changes in temperature by producing an electrical current that causes the gas valve that supplies the pilot light to open when the temperature is high or to close when there is no direct heat source. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. I would recommend a professional do the work in replacing the gas valve. +44 (0) 1246 261999 websales@peaksensors.com In our area at 5600 ft our gas value is only 825 btu per cubic ft. A thermocouple is a sensor for measuring temperature. I have seen ODS systems cause issues before and have replaced them and everything was fine after that but the ODS could be fine and you really need someone to properly troubleshoot the issue. This further supports a thermopile issue. If it does not detect a flame, it shuts off the gas supply. After inserting the probe, tighten it (in place) using the Chemthread cap. my gas stops flowing to the pilot after a few minuets on my ventfree logs my flame is not lifting off of the thermocouple good voltage reading on thermocouple. But,It didn’t burn it up(only tested for a few seconds). The valve will stay open if I connect a AA battery(I know I am putting way too much voltage). What is the thermocouple millivolt range for a good thermocouple? And you do know there is a difference between a thermopile and a thermocouple? This website uses cookies to improve your experience. Include your email address to get a message when this question is answered. This website uses cookies to improve your experience while you navigate through the website. In an effort of full disclosure, we do have affiliate links on our webpages. A yellow or orange flame means the system needs to be cleaned. Furnace, water heater, ovens and more all use these. Not sure I want to do that. 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. This sensor consists of two dissimilar metal wires, joined at one end, and connected to a thermocouple thermometer or other thermocouple-capable device at the other end. The thermocouple was used to hold the pilot valve open. BTW, it never exactly said what you wrote but may have implied it for those who lack common sense. References. The thermocouple on your gas furnace is a heat-sensitive device that transmits a small electrical signal to the gas valve to keep it open when the pilot is on. If you’re still unsure or don’t have a working pilot light, test the thermocouple with a multimeter. Finally, NOW TURN THE METER TO VOLTS. You have to be careful when cleaning it. I did know that I just didn’t take it into account when I made the tool. Thanks to all authors for creating a page that has been read 32,245 times. without Turing on the flame or fire ? An electric current then flows through the loop (which is effectively an electric circuit) and the size of that current is related … Remove the Old Thermocouple Using an open-end wrench, unscrew the nut that holds the thermocouple end fitting into the gas control valve. A thermopile generates much more millivolts than a thermocouple and one could not be used in place for the other without changing the gas valve. So how does a thermocouple work?The voltages generated are extremely small, generally only a few microvolts per degree of temperature difference. Thirdly, start the flame and put the tip of the thermocouple in the fire. Grasp the sides and pull the panel up and away. Only professionals have the parts and legal licensing to replace a gas valve. This article was co-authored by Gevorg Grigorian. Set the multimeter to read millivolts, then start the pilot and have your helper hold in the gas control knob to keep it burning. That will help with a furnace thermocouple test. Anyway, as you suggested, I have ordered a thermopile that is compatible with my unit. The thermocouple is a device made up of two dissimilar metals. By signing up you are agreeing to receive emails according to our privacy policy. It consists of a heat sensor connected to a solenoid; when the sensor is not heated by the pilot flame, the solenoid closes the gas supply line. {"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":"