how to test a thermocouple

If the thermocouple is putting out 26 mV then something is wrong with the valve. A thermocouples uses a sensor to measure the temperature of current passing through an object. While thermocouples use millivolts to determine the temperature, the millivolt reading will not be Touch the two leads together from the meter, and … You know you have gas, and everything seems to be fine so what is the problem? Switch the settings to read millivolts, and then connect your meter's test leads to the wires of the thermocouple. Carefully remove the faulty thermocouple from the gas appliance. "Very clear and simple drawings make it easy to learn the basics in a short time. I have a tank top propane heater that won’t stay lit. If the pilot light doesn't stay lit, check the gas water heater thermocouple by keeping the pilot button depressed. If your thermocouple is coated with a white, chalky material, this may indicate it's not functioning properly. If you suspect this is the problem instead of the thermocouple, call a professional. 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. As the name itself suggests, this test is performed by placing the thermocouple … Thanks to all authors for creating a page that has been read 32,151 times. ODS is an oxygen depletion sensor. When the pilot is on, the fireplace turns on readily when I flip the wall switch. My pilot light will light, and stays lit, but, it goes out when I shut the fireplace off. They are joined together at the tip (Hot Junction). How to test a thermocouple – The best instrument to use is a thermocouple thermometer as this will give you a temperature measurement rather than a voltage which will mean much less. 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. You know you have a problem. If the resistance is minimal (less than one ohm), the circuit is continuous. They will replace the thermocouple when they do this. If you’re still unsure or don’t have a working pilot light, test the thermocouple with a multimeter. You ask a friend, and the friend tells you the thermocouple is bad. Attach one clip on one end of the thermocouple and attach the other clip on the other end, that is the one that gets screwed into the gas valve. Any thoughts? Gas valves cannot be repaired and in some municipalities require a licensed professional to install. That allows the main valve inside the gas valve to feed the main burners with gas. Thanks for the info. Let the Testing Begin!. Finally, Good luck! We did add the following: *At sea level. BTW, it never exactly said what you wrote but may have implied it for those who lack common sense. But,It didn’t burn it up(only tested for a few seconds). The thermocouple is a simple, widely used component for measuring temperature. Thank you.". Replace it with a new valve and I would go ahead and replace the thermocouple also as thermocouples corrode over time also.Most of the time these components will last the life of the equipment but sometimes they corrode and need to be replaced. With the leads apart, you will read infinity. Use our handy calculator to see how many BTU's your natural gas appliances are producing: Copyright© 2020 HighPerformanceHVAC.com |. How to Test a Thermocouple: 14 Steps (with Pictures) - wikiHow Save www.wikihow.com. This is a common problem with thermocouples. This further supports a thermopile issue. My analog multi-meter cannot discern sub-unit readings, I need to get a digital one that does. To test for this, please move your thermocouple wires around with a plastic pen. By using this service, some information may be shared with YouTube. Locate the pilot light controls on the gas valve. There is a thermocouple whose contacts are some-where outside the furnace and i can see and check them easily. Your a buffoon. A standing pilot gas valve has two inner valves, one for the pilot light and one for the main valve. you need to apply heat to the tip of the thermocouple to get a reading on your meter as explained in the article. Check for continuity by using a multimeter set up to measure ohms.Connect the multimeter test leads to the 2 thermocouple leads (polarity doesn’t matter for this test) and if the meter reads 0 or open circuit, then at least one of the thermocouple leads are broken. A weld joins the two metals. This article was co-authored by Gevorg Grigorian. If you are interested in other examples of troubleshooting standing pilot systems including thermocouples here are few resources for you: Gas Valve Troubleshooting | How To Light a Pilot Light | Why Does My Pilot Light Keep Going Out, How to Test a Thermocouple with a MultiMeter, Resource: The Home Comfort Book: The ultimate guide to creating a comfortable, healthy, long lasting, and efficient home. Use the multimeter to take a reading of the resistance of the circuit. The thermocouple needs to heat up for 30 seconds to 1 minute in order to obtain a proper reading. The amount of emf generated is different for different combinations of the metals.2) Peltier effect: As per the Peltier ef… Gevorg holds a BS in Business Administration and Management from California State University-Northridge. It also is good for water heater thermocouple testing. How to test a thermocouple. Locate the gas tank, which is in the basement or lowest floor of your home. As you said, you put way too much voltage on it. By signing up you are agreeing to receive emails according to our privacy policy. Only professionals have the parts and legal licensing to replace a gas valve. If the pilot goes out, relight it and check the flame. Put on meter lead directly on the gas valve side of the thermocouple. This planet needs more geniuses like you around. Lastly, replace it. The first solution combines both reference-junction compensation and signal conditioning in a single analog IC for convenience and ease of use; the second solution … Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. If not then that could lead to problems. Necessary cookies are absolutely essential for the website to function properly. Good luck! It is consuming too much air. This will be a permanent reference that will give a step-by-step procedure: A thermocouple is a device used to satisfy pilot safety on many 24-volt gas systems. Secondly, turn on the meter and set it to Ohms. No, you need to find that particular part or one specifically for gas logs. Yes you should have a pilot adjustment try turning the pilot a little higher. This website uses cookies to improve your experience. Gevorg Grigorian is an Appliance Repair Specialist and the Owner of G and R Appliance Repair in Los Angeles, California. 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. By using our site, you agree to our. If the thermocouple is testing good then you likely have a bad gas valve. Gevorg holds a BS in Business Administration and Management from California State University-Northridge. This guy writes a helpful article and makes one small mistake and you call him a idiot. Put the other lead on the copper line as shown by my right hand in the picture above. Closed Circuit Test. Next, take your meter and set it to ohms. They can troubleshoot the problems and replace the thermocouple if necessary. The thermocouple, which operates as a safety device, turns the gas supply off when the pilot light goes out. Gevorg Grigorian is an Appliance Repair Specialist and the Owner of G and R Appliance Repair in Los Angeles, California. 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. Knowing how to test a thermocouple with a multimeter is an important step … We did have this addendum on our calculator when we published the calculator originally. The thermocouple is soldered to a bracket that the thermocouple/thermopile/ignitor/gas nozzle are affixed to. So how do you test the thermocouple to see if it is bad or not? Obtain a volt meter and turn the dial to resistance ( Ω). Locate the gas tank, which is in the basement or lowest floor of your home. 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. What is the thermocouple test procedure? I suggest you use some sandpaper to remove the powder and see if that fixes the problem. With over 13 years of experience, Gevorg specializes in residential and commercial appliance repairs as well as heating, ventilation, and air conditioning (HVAC) services. It is likely a thermopile although there are some ventless gas logs that use thermocouples also. Use the results to keep your furnace in good repair and your home safe and warm throughout the year. Touch the two leads together from the … Therefore, if the pilot light was not lit or the thermocouple was bad, the main valve could not open. You are a freaking jerk. If so then it is good. There are 15 references cited in this article, which can be found at the bottom of the page. Everything is in alignment to the flame. Locate the pilot light controls on the gas valve. Lastly, Gas valves cannot be repaired as per any manufacturer. This commission helps us pay for the overhead of running this website. Temperature differential. Ignite a lighter, or other heat source with a flame, at the opposite end of … We also use third-party cookies that help us analyze and understand how you use this website. So, I’m not sure if I have a thermocouple or thermopile issue. I did know that I just didn’t take it into account when I made the tool. The thermocouple millivolt range should be above 25 millivolts. That is simply a test to check the meter for continuity. Never use anything abrasive to do so as you could damage the thermopile or thermocouple. How to Test a Thermocouple with a Multi-Meter step by step: Thermocouple fits securely in the pilot burner (pictured above). This end appears needle-shaped and is designed to take on heat, so put the tip into the flame. To check the thermocouple, pick a sample. by High Performance HVAC | Gas Furnaces | 15 comments. Air that you need to live. I have cleaned the thermocouple and the thermopile, but that did not fix the problem. “Calculation is based on the Approximate Heat Content (BTU Value) of Natural Gas as published by the Energy Information Administration for 2017”. The thermocouple is putting out 26mV so I would think that would be good. 1 millivolt is equal to 1/1000 of a volt. This website uses cookies to improve your experience while you navigate through the website. Manufacturers/Contractors derate gas appliances in elevations over 2000 feet. How to Test a Thermocouple with a MultiMeter? Is there any method to check this thermocouple with Digital |Multi Meter ? With your meter ready, restore the flow of gas and turn it to the "pilot" setting. One probe of the meter should be connected to the copper sheath of the thermocouple … 14D0473. The millivolt thermocouple range. without Turing on the flame or fire ? How to Test a Thermocouple for a Water Heater – Everyone who has owned a gas heater including furnaces or water heaters will know that from to time you have to light the pilot light unless you have the electronic ignition that automatically lights the pilot light. The three main tests used are the open circuit test, closed circuit test and resistance test. wikiHow is where trusted research and expert knowledge come together. What should I do if my thermocouple is coated with a white powder? A thermocouple is a safety device for a standing pilot gas system. {"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":"

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