how to fix a bad thermocouple

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. And the worst part is that you can have a bad thermocouple without even knowing. Ive seen quite a few appliances require turning and holding the valve to control. Shut Off The Gas Supply 02. The tube sits above the bracket, a nut holds the bracket and wires in place, and underneath the bracket, you will see the copper lead wires that connect to the gas valve on the furnace. Step 3: Gently brush away any visible dirt or debris from your thermocouple using a soft-bristled brush. Don't try to adjust the mechanism or tamper with the gas line. If the resistance measurement shows a dead short from pin to pin, check the thermocouple itself first. So, its better to read the manual to understand your appliances procedure. Nothing lasts forever, and when the thermocouple wears out, the pilot won't stay lit and your appliance won't work. The pilot light controls, reset buttons, gas valves, and thermocouple are usually contained in an assembly at the front of the furnace. 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. 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. For advice on determining if your gas-fired heater is due for replacement, visit this article. Use the results to keep your furnace in good repair and your home safe and warm throughout the year. Overtightening it can prevent the flame from lighting. A working thermocouple will give a reading of between 25 and 30 millimeters. Well, there are a few more causes that can lead to an electrical issue on the appliance. 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. Now that is working again, it shows about 15 ohms. A burned out or broken thermocouple should be replaced. The No. If there is a safety or reset button, push the button, and keep it depressed. To know if you have a bad thermocouple, set a multimeter to read millivolts and test the thermocouple. The clamp that holds the thermocouple may be hot. Sometimes youll notice tour appliances arent lighting or lighting sporadically. 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. Problems occur when the gas flow is obstructed or misdirected, or when the pilot is blown out. Be sure to turn off the power to the device before attempting to remove the thermocouple. Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place. The thermocouple doesnt have wires. Use any type of steel wool or emery cloth to wipe off any dirt. The device can get dislocated while cleaning or other maintenance. Set the multimeter to read millivolts, then start the pilot and have your helper hold in the gas control knob to keep it burning. The procedure for lighting a standing pilot always includes lighting the flame, then manually holding in the gas valve to keep the flame burning and give the thermocouple time to heat up. This end appears needle-shaped and is designed to take on heat, so put the tip into the flame. In that case, you have to replace a new thermocouple. It may have gotten crushed or one of the wires may have broken off. He worked in the trades part-time while serving as an active firefighter. Dirty Pilot Burner Orifice 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. Step 4: Under the bracket, screw the bracket nut over the tube. The thermocouple has two dissimilar metals that form an electrical circuit. 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. Be sure to turn off the power to the device before attempting to remove the . It should be low, but definitely not a dead short. Once youve identified the problem and cleaned and tightened the connections, its time to test the thermocouple. Then attach the black clamp to the gas valve. Question: How do you bypass a thermocouple? The first step is to make sure that the appliance is off. 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. Gevorg Grigorian. Unhook Everything From the Gas Valve 03. You will need a wrench, multi-meter, and a flame source, like a candle or a lighter, to perform the test. 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. No wonder that it is also used in the water heater. This is often not realized and overlooked during troubleshooting. The pilot should heat the top 7/8" of the thermocouple with a clean (blue) flame. I can solder wires with the fine tip just fine at 260 degrees celsius, but it takes about 300 degrees to do SMD parts. Clean the threads of the connecting nut with a pencil eraser and re-tighten. Mostly, they are connected through a thin copper tube. When it stops working, the furnaces pilot light also turns off. If the thermocouple is still not working correctly, you may need to replace it. When the flame is weak, boost up the flame to reach the device. Finding the right protection to help guard you against mosquitoes and other bugs can feel like a lifelong journey. Compatible Thermocouple Calibration Type? 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. 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. Lets be apart from here. Wait until your thermocouple properly generates heat. By using our site, you agree to our. A correctly adjusted pilot flame is steady and blue, and stands between 1/4 and 1/2 inch high. Your furnaces thermocouple is usually located right in the flame of the furnaces pilot light. How Does a Gas Water Heater Thermocouple Work? Remove your thermocouple from the heater using an 8mm wrench. When a pilot goes out, relighting it is simple: Step 1: If there is a gas valve at the pilot, turn the valve to the OFF position and wait at least three minutes to let any built-up gas dissipate. If the thermocouple isnt bad, then whats creating a problem? Then, when the pilot is burning brightly, release the reset button. How to know if a thermocouple is bad? 2 May 2006. You can also eliminate obstructions in the pilot tube as a possible cause by turning off the gas, unscrewing the pilot tube from the gas valve and blowing compressed air from a can through the tube. 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. Once you have located the thermocouple, do a visual inspection. Ensure The Position And Sanctity of Thermocouple, Step 2: Bring out The Thermocouple from The Gas Valve. Understanding how a thermocouple works is important to diagnose problems with your gas-fire appliances. On his retirement, he started a remodeling and home repair business, which he ran for several years. Gas valves cannot be repaired. Now, remove the valve using pliers. Stocking the largest selection of appliance parts, heating, plumbing, lighting, and janitorial supplies, AMRE ships almost anywhere in Canada within 24 - 48 hours. Do You Need to Hire an Electrician? Yet, there are multiple causes behind the workflow being hampered. If you found your way here and managed to fix your thermocouple, leave a comment and let me know how yours was broken and how you fixed it. The thermocouple is a small electrical device, but it is a critical safety component on your furnace. {"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":"