Step 3: Insert a new thermocouple into the hole in the bracket, steel tube facing up and copper lead down. Turn the gas valve on the appliance to the Light Pilot setting. A good pilot light flame is blue. Support wikiHow by Use a can of compressed air to gently blow away any dust and dirt from the thermocouple. If the connections appear loose or corroded, then you will need to clean them and tighten them. Sometimes you don't need to spend a single buck, and a little cleaning will do the trick for you. Turn On Gas Supply And Check for Leaks First, light the pilot light and keep observing the voltage meter. The thermocouple, which operates as a safety device, turns the gas supply off when the pilot light goes out. Finally, its important to properly maintain your thermocouple to ensure it works correctly for a long time. Do You Need to Hire an Electrician? Or else, therell be a huge possibility of a sudden burst of flame from the burner. The actual thermocouple on mine is just a bare metal ball. Why Wont My Furnace Ignite? In any case, Ive been comparing the temperature at the tip of my new iron to the measured temperature on the display. If the thermocouple is malfunctioning, the most likely culprit is a loose connection. Pilot hood and flame direction. To replace a thermocouple: Step 1: Unscrew the copper lead and the connection nut inside the threaded connection to the gas line. How To Fix: Start with cleaning the thermocouple. If the thermocouple still doesnt work and your appliance operates sporadically or not at all, further testing is required. The pilot light is a small open flame that is fed by a steady flow of gas. Better to be safe than sorry. Some thermocouples will look slightly different, so check your furnace manual. Be sure to turn off the power to the device before attempting to remove the thermocouple. Whatever you do, never use any cleaning products or liquid of any kind. To test the thermocouple, it must be hot. If you suspect this is the problem instead of the thermocouple, call a professional. 2. 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. The job of the thermocouple is to keep the pilot lit. It is usually found near the system's pilot lights or burners. Others require that you push the gas valve in to open the valve to the pilot light. Regularly inspect the connections for signs of corrosion or loose wires. A malfunctioning thermocouple can lead to inaccurate readings and can even cause your heating or cooling system to shut down. Get free, zero-commitment quotes from pro contractors near you. When a thermocouple fails, the pilot light won't stay lighted. If you buy through links on our site, we may earn a commission. How To Replace Thermocouple On Gas Water Heater? Replacing a thermocouple is a relatively easy fix that can take less than two hours. There are all sorts of methods out there. If your appliance wont light or only lights sporadically, the most common problem is build-up on the igniter. Remove the valve using your pliers. FIND LOCAL CONTRACTORS. Keep reading to find out how to maintain and repair one of the most vital components of any machine. Step 1. To do this, youll need a voltmeter with a thermocouple probe. The first step in repairing a thermocouple is to identify the problem. Do this until the end of the thermocouple sits squarely in the flame of the pilot light. How To Get Rid Of The Made In China Smell 7 Methods to Try! A functioning thermocouple should also show a few millivolts DC when hot. An exposed junction thermocouple offers the fastest response. Be sure to turn off the power to the device before attempting to remove the . Before jumping to the conclusion that the thermocouple is at fault, look at the pilot flame. There are numerous reliable yet affordable socket sets on Amazon if you don't have a socket wrench. The idea is to make that sensor portion really hot. When purchasing a new thermocouple, be sure to check the specifications to make sure it is the correct size and type. And the worst part is that you can have a bad thermocouple without even knowing. By following the steps outlined above, you can easily repair a malfunctioning thermocouple and get your heating or cooling system back up and running in no time. 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 youve got a few minutes to spare, stay with me! Compatible Thermocouple Calibration Type? Youll know you did it wrong if you measure the temperature of some hot thing and the displayed temperature drops instead of rising. Thanks to all authors for creating a page that has been read 100,018 times. For advice on determining if your gas-fired heater is due for replacement, visit this article. 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. Once youve purchased the replacement thermocouple, simply disconnect the old thermocouple and connect the new one in its place. Your thermopile voltage should be between 650mV and 800mV. Stocking the largest selection of appliance parts, heating, plumbing, lighting, and janitorial supplies, AMRE ships almost anywhere in Canada within 24 - 48 hours. If so, strip back some of the insulation, cut both bare wires to the same length, and reattach the wires. Step 3: Gently brush away any visible dirt or debris from your thermocouple using a soft-bristled brush. Here's how to check and fix your thermocouple: Measure the resistance from pin to pin on the plug. The thermocouple may get faulty if dirt builds upon and around it. 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. In fact, they often make themselves known at sunset and can eat you alive before dusk has ended. A small electric current goes to the auto-igniter when the gas valve signals the gas to turn on. 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. Wipe away any remaining dirt or soot on the thermocouple with a clean, dry cloth. *** As an Amazon Associate I may earn from qualifying purchases at no extra cost to you. Use an 8mm wrench to pull off the thermocouple. Using a small pair of needle-nose pliers is a safe way to adjust the thermocouple clamp. Nothing lasts forever, and when the thermocouple wears out, the pilot won't stay lit and your appliance won't work. You might also get a splatter or crumb of solder or other metal between them. All information is subject to change at any time without notice. Appliance Repair Expert. It might help to put a piece of heat shrink tubing over one of the wires before reassembling it. 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. I understand this seems quite confusing for you. Your thermocouple voltage should be between 25mV and 30mV. Thank you.". By creating an account you agree to the Hunker, How to Change a Thermocouple on a Fireplace. I know this is the first question that hits your mind. So that it can produce an ample amount of electrical flow. Take off the valve housing aside through a 133mm socket wrench. [8] The tube connects to the gas valve below the pilot light. Or you might catch an electrical fire on your appliance. How To Clean a Thermocouple. drawings. It does this by sending a tiny electric current to a sensor on the gas valve signaling the valve to stay open. Lets be apart from here. I know its really hard to tell if it has started to malfunction or not. First, inspect the flame. Adjust the pilot until it appears strong and covers the sensor as previously described. Turn the appliance off. Once youve identified the problem and cleaned and tightened the connections, its time to test the thermocouple. You may have more pressing problems than a thermocouple in your gas-fired heater. A working thermocouple will give a reading of between 25 and 30 millimeters. If the voltage meter counts less than 25 millivolts, its the thermocouple. If the flame lights and goes out when you release the gas control knob after holding it in for the recommended 20 to 30 seconds, that's the sign of a thermocouple malfunction. If the thermocouple is still not working correctly, you may need to replace it. THERMOCOUPLE FUNDAMENTALS Service Life The following are the six most common causes of thermocouple measuring errors, followed by ways to rectify them: 1. Finally, put back the thermocouple inside the box. If youre uncomfortable performing this test yourself, be sure to call a licensed HVAC contractor who can help you. Remove the thermopile wiring connector from the gas control. Step 3: If the pilot flame won't stay lit after several tries, it should be adjusted by a professional. 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. To help you, I am leaving a list of the most effective voltmeters-. If a water heater pilot won't light at all, the thermocouple probably isn't the problem. Finally, we will count the voltage level in the upcoming segment. Then delicately drag out the thermocouple. Separate the thermocouple connector from the gas valve. That may not be a safe assumption, but I havent got anything else to go on. 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. When these two metals are heated, they produce a measurable electrical current. Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place. There may be other issues with your appliance that can lead to problems, so you should eliminate these possible issues first. If the connections appear corroded or loose, be sure to clean them and tighten them. I fiddled with it for a while, then figured it was time to order a new thermocouple. A dirty thermocouple may affect the ability of the gas fireplace to ignite. The welded end of the thermocouple probe should protrude at least 1.5 inches (0.0381 meters) into the kiln chamber. 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. A working thermocouple will produce a reading of 25 to 30 millimeters. Check the thermocouple for the correct depth of immersion. Use a lighter or torch to hold a flame under this end. 2. Often the thermocouple connection points are overlooked, but are critical for proper readings. Set your voltage meter to read voltage (V) in millivolts. Check the following: 1. And put off the thermocouple connector from the gas valve. They can also get twisted and short out. 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. Next, use a multimeter to check for continuity of the heater zones. Though you have cleaned the device with a soft hand. If the appliance should suddenly light the burner, you may suffer burns or worse injuries. 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. The likely problem, again, is an obstruction in the pilot tube. 1 cause of pilot lights that won't stay lit is a worn-out thermocouple. With it all reassembled, the meter was again showing the correct temperature. customerservice@temprel.com. 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. But, if you discover that the voltage level is accurate, then your gear is not faulty at all! 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. Working on a gas appliance with the gas on is an open invitation to an accident and severe burn injuries. Your voltage meter has two probes, one red and one black. Dirty Pilot Burner Orifice Ive also found that it takes a higher temperature to solder with a fine tip than with a blunt tip. If there is no reset button or gas valve, simply hold a lighted match to the pilot orifice. If your equipment calls for a J type, you will need to replace with a J type. 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. Save my name, email, and website in this browser for the next time I comment. Never work on a gas appliance, especially around the burners, igniters, or pilot lights with the gas turned on. By signing up you are agreeing to receive emails according to our privacy policy. Cleaning the thermocouple is a pretty simple process but should only be done when the fireplace is turned off and is completely cool. Your furnaces thermocouple is usually located right in the flame of the furnaces 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. Were committed to providing the world with free how-to resources, and even $1 helps us in our mission. Yet, there are multiple causes behind the workflow being hampered. 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. The voltmeter will measure the electrical potential between the thermocouple and the gas valve. Understanding how a thermocouple works is important to diagnose problems with your gas-fire appliances. Lastly, observe the reading of the voltage meter. Purchasing a new thermocouple to find out how to check the specifications make. Were committed to providing the world with free how-to resources, and when thermocouple... Put back the thermocouple connection points are overlooked, but are critical for proper readings thermocouple! 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Connect the new one in its place us in our mission often make themselves known at sunset can! Start with cleaning the thermocouple with a clean, dry cloth time without notice fine. And dirt from the gas valve figured it was time to order new!