Your thermocouple voltage should be between 25mV and 30mV. You can test this yourself using a multimeter, but you may need a helper to keep the pilot flame burning while you do it. Make sure that the wiring is protected with insulation and is not damaged or broken anywhere in the circuit. 30 July 2020. Then lets get your work done! By creating an account you agree to the Hunker, How to Change a Thermocouple on a Fireplace. 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. Thanks to all authors for creating a page that has been read 100,018 times. It is often colored silver or red. For that, turn on the gas valve and put it in the Light Pilot setting. Any material that is added to the connection points will influence the readings as they are being cooled by the surrounding ambient air. Shut down all power sources connected to your heating system while wearing safety gear such as goggles and gloves. You might also get a splatter or crumb of solder or other metal between them. 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. While putting it back together, I put a small piece of heat shrink tubing over one of the wires inside the plug. How To Get Rid Of The Made In China Smell 7 Methods to Try! A thermocouple costs about $20, so you can save quite a bit of money if you do the work yourself. So that it can produce an ample amount of electrical flow. Remove The Burner Assembly 04. Carefully remove the thermocouple from the gas valve by loosening the copper connector. If the connections appear corroded or loose, be sure to clean them and tighten them. If the thermocouple isnt bad, then whats creating a problem? The information on this website is for informational purposes only; it is deemed accurate but not guaranteed. If you can't get the flame to light at all, and you're sure the gas is on, there's probably an obstruction in the pilot tube. Expires 04/30/23 Cannot be combined with other offers. That may not be a safe assumption, but I havent got anything else to go on. Just the fact that you have to shut down and replace a thermocouple means lost revenue. This instrument contains two probes; red and black. Adjust the pilot until it appears strong and covers the sensor as previously described. Some thermocouples will look slightly different, so check your furnace manual. After three minutes, turn the valve to the PILOT position. 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. Richmond Water Heater Thermocouple Replacement: The How-To Steps 01. If the connections appear loose or corroded, then you will need to clean them and tighten them. Many new appliances have auto-igniters that take the place of the pilot light. 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. When these two metals are heated, they produce a measurable electrical current. Turn off the fireplace gas valve and remove the front panel from the fireplace. Replacing a thermocouple is a relatively easy fix that can take less than two hours. Its because of the dirt build-up inside the igniter. If the resistance measurement shows an open circuit, look closely at the thermocouple itself. Must present coupon at time of service. When it stops working, the furnaces pilot light also turns off. These can be easily dislodged during cleaning or other maintenance, especially if the covers are left off the appliance. When the flame is weak, boost up the flame to reach the device. A functioning thermocouple should also show a few millivolts DC when hot. Meanwhile, dont forget to maintain safety measures. Use any type of steel wool or emery cloth to wipe off any dirt. Hopefully, you have understood how to find out the issue. Just using the probe had twisted the wires around inside the strain relief and shorted them. Or you might catch an electrical fire on your appliance. We use cookies to make wikiHow great. Finally, we will count the voltage level in the upcoming segment. To do this, youll need a voltmeter with a thermocouple probe. Answer: You can only place the pilot flame at a specific distance from the thermocouple. When a thermocouple fails in your control system, bad things happen. To bypass the thermocouple: Move the tilts switch wire aside. What does a thermocouple look like and how do you find it? Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place. Your Promotional Selection Has Been Applied! After a minute, check the thermocouple with the multimeter if its less than 25 millivolts, you need to replace it. Turn the gas valve on the appliance to the Light Pilot setting. Problems occur when the gas flow is obstructed or misdirected, or when the pilot is blown out. Lastly, observe the reading of the voltage meter. Step 3: Gently brush away any visible dirt or debris from your thermocouple using a soft-bristled brush. If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. A burned out or broken thermocouple should be replaced. On some gas cookstoves, the igniter may be inside the sealed burner assembly. It should have a yellow tip and cover the tip of the thermocouple. Here Ive shown a 5-step method to find out if your thermocouple is bad or not. , it must be hot. This article was co-authored by Gevorg Grigorian. The pilot can go out for a number of other reasons, however, so if you're having trouble getting the pilot to stay lit, the thermocouple may not be at fault. The only way for that to be possible (lower resistance at the plug than at the thermocouple) was for there to be a short in the wiring in the plug. To gain access to the pilot burner, pull the door out of the furnace housing. Now that is working again, it shows about 15 ohms. All you need to do is scrape the thermocouple clean and then dry-wipe the residue. A good pilot light flame is blue. Like the other component parts in your furnace, the thermocouple can wear down over time, producing lower voltage than it should when heated. If the pilot lights but the flame goes out as soon as you release the button after holding it for 60 seconds, then the thermocouple is bad. If so, unscrew them from the pins and untwist the wires. Overtightening it can prevent the flame from lighting. If so, strip back some of the insulation, cut both bare wires to the same length, and reattach the wires. 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. In our final section, we will conclude our discussion of repairing major appliances with a detailed examination of -- of course -- motors. If the thermocouple isnt problematic, search for the actual valid reason. This procedure is a bit more involved and requires a voltage meter. 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. For advice on determining if your gas-fired heater is due for replacement, visit this article. Your gas appliance checks for this electrical current to make sure that the pilot light is working. Ive seen quite a few appliances require turning and holding the valve to control. Next, use a multimeter to check for continuity of the heater zones. 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. Newer gas appliances have igniters that start the pilot light as needed. Now that is working again, it shows about 15 ohms. Before the test, turn off the gas supply because you must first remove the thermocouple. The plug fit better and held tighter, but still no temperature. On 2020-07-15 by Don Gilbert Use a lighter or torch to hold a flame under this end. Auto-igniters are quite simple. Its copper tubing makes it easy to spot. Mine showed about 0.1 ohms when it wasn't working. You may have to wiggle it a bit before it comes loose. How To Install A Thermocouple On A Water Heater. Use the results to keep your furnace in good repair and your home safe and warm throughout the year. A damaged heater can turn on the gas oven automatically. After that, generate heat on the thermocouple. Five time constants are required for the sensor to approach 100% of the step change value. References. Thermocouple Probes with Attached Connectors, Thermocouple Probes with Transition Joint. FIND LOCAL CONTRACTORS. By using our site, you agree to our. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); How to Fix a Thermocouple on a Water Heater? 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. First, inspect the flame. There are numerous reliable yet affordable socket sets on Amazon if you don't have a socket wrench. Then delicately drag out the thermocouple. Reading the voltage level is the last step to find out the real cause. Better to be safe than sorry. 1 cause of pilot lights that won't stay lit is a worn-out thermocouple. Check the following: 1. If there is a safety or reset button, push the button, and keep it depressed. I checked the internet, and found that a properly working K-type thermocouple will have pretty much no resistance when measured with an ohmmeter. Experts suggest counting the voltage (v) in millivolts. Well, there are a few more causes that can lead to an electrical issue on the appliance. 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. In this situation, you can easily diminish the issue by following a few simple maintenances. Finally, put back the thermocouple inside the box. The thermocouple needs the full heat of the pilot light to create enough electrical current. If you find a dead short from pin to pin, check the inside of the plug and see if the wires are twisted. The thermocouple on your appliance is with the pilot light. If the flame goes out repeatedly, it may be getting too little air; if it's yellow at the tip, it's getting too much air. So, its better to read the manual to understand your appliances procedure. The voltage meter should read about 30 to 40 millivolts when the thermocouple has reached the proper temperature. 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. To operate correctly, a thermocouple requires the full heat from the pilot light. You can test this yourself using a multimeter, but you may need a helper to keep the pilot flame burning while you do it. Include your email address to get a message when this question is answered. Turn on the pilot light (following instructions for relighting the pilot light carefully) and make sure about 1/2-inch of the thermocouple extends into the pilot flame. If you have gas-fired appliances such as a water heater, space heater, or cookstove, these appliances may have one or more thermocouples. Your thermopile voltage should be between 650mV and 800mV. Gevorg Grigorian is an Appliance Repair Specialist and the Owner of G and R Appliance Repair in Los Angeles, California. Generally, thermocouples have no wire connections. Your email address will not be published. Though you have cleaned the device with a soft hand. He worked in the trades part-time while serving as an active firefighter. Performing a few simple inspections and maintenance may solve your thermocouple problem without the need to install a new thermocouple. I took the meter apart, disassembled the jack, tightened the pressure on the spring contacts, and reassembled the whole thing. If the thermocouple is out of alignment, gently pull or push the spring clamp. With over 12 years of experience, Gevorg specializes in residential and commercial appliance repairs as well as heating, ventilation, and air conditioning (HVAC) services. There are 9 references cited in this article, which can be found at the bottom of the page. However, if you need a professional to do the job, you can pay $120 to $150. If you suspect a bad thermocouple, diagnosing the problem may not be all that difficult. Looking at the pilot light and the thermocouple, most of the thermocouple should be in the flame of the pilot light. THERMOCOUPLE FUNDAMENTALS Service Life Next, take your meter and set it to ohms. Such as the gas heater, auto ignitor, and pilot light. And put off the thermocouple connector from the gas valve. It can result in overrunning your central heating pump. 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. But you can discover those issues by going through some easy investigation. It may have gotten crushed or one of the wires may have broken off. If youre uncomfortable performing this test yourself, be sure to call a licensed HVAC contractor who can help you. Answer: Unscrew the tilts switch wire. If your pilot light doesnt work, use the wrench to unscrew the thermocouples other end. Soot, spilled food, or other contaminants will often build up between the spark gap and prevent the igniter from arcing. Note: Only clean an orifice with compressed air as drill bits and other abrasive items can enlarge the opening. Your appliance may not have a pilot light or a thermocouple. This device is manufactured in a variety of styles, models, and technical specifications. 2. Learn about the Maintenance and Handling of Thermocouples, Email: Turn off the fireplace gas valve and remove the front panel from the fireplace. So, when you lose a temperature sensor - like a thermocouple - you need to know why it failed and how to prevent it in . The Red wire is generally the negative (-) wire in thermocouples, harnesses, and cables. If you suspect this is the problem instead of the thermocouple, call a professional. 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. 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. Only professionals have the parts and legal licensing to replace a gas valve. The first thing you need to do is set up your multi-meter for direct current and set the range for less than one volt or set it to millivolts. For more specific instructions on operating your multimeter, read the owners manual. Turn the appliance off. Get out of the house, leaving the door open, and call the gas company or the fire department immediately to report a leak. Put Everything Back Into Its Place 07. 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. The main reason for the decalibration is that the wires can become chemically attacked, which effects the wire composition, mechanical properties of the material and ultimately the temperature readings. Then attach the black clamp to the gas valve. Or youll need another helping hand to share your hand for the rest of the task. A thermocouple lasts for an average of 10 years, and you need to replace yours if there is too much rust on it. A thermocouple is a device that produces a small electric current when it is heated. An old toothbrush is a perfect tool for this job. In most cases, the thermocouple attaches to the gas valve with a thin. By using this service, some information may be shared with YouTube. 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