Favorite Answer. After cleaning, should the pilot light still not stay lit, it is probably time to get new equipment. So the pilot on my furnace wouldn't stay lit. Pilot light won't stay lit after initial furnace burn. I tested the thermocouple with my multimeter and got 29 millivolts which meant it was still working. These furnaces skip steps 3-5 and instead light the burner directly. Is it common for thermocouples to test fine but still not actually work? furnace pilot went out , replaced thermocouple, pilot won't stay lit? Anonymous. My furnace pilot light will not stay lit. Cleaning the thermocouple is a pretty simple process but should only be done when the fireplace is turned off and is completely cool. Assuming I was in over my head, I called the plumber who proceeded to change the thermocouple and now everything is fine. The pilot stays lit anywhere from 20 minutes to several weeks. If you have a furnace with a pilot light, then you will have a thermocouple. If cleaning the thermocouple didn’t allow your pilot light to stay lit, or cleaning the thermopile didn’t allow the pilot light to generate enough electricity to open your gas valve and ignite the burner, it might be time to replace one of them. 1 decade ago. Step 5. The pilot light won't stay on. You can test it with a multimeter. The easiest way to tackle this home project is to abrade the rod with fine-grit sandpaper lightly. Other Reasons for Gas Fireplace that Won’t Stay Lit … read more. Maybe the pilot stays on for a moment and the furnace attempts to fire, but almost immediately shuts down. A Broken or Damaged Thermocouple – In this instance there is something wrong with the equipment and a technician would be required to replace or repair the thermocouple in order for your pilot light to stay lit again. I've tried two new thermocouples, and I can't get it to stay on. Attempts to re-light the pilot light are futile. When you push the thermocouple closer to the pilot, it will solve the problem. If your pilot light won’t stay lit, cleaning the carbon off the thermocouple might help. Maintenance or troubleshooting should only be performed by adults familiar with operating large gas appliances. The thermocouple detects the pilot light via sensors. Luckily, this is a relatively simple procedure with the right tools and equipment. Adjustments for your furnace thermocouple. Step 3: If the pilot flame won't stay lit after several tries, it should be adjusted by a professional. The tip of the thermocouple is positioned in the flame, keeping the tip heated at all times. 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. I have an older ruud furnace. Furnace Pilot Light Won't Stay Lit - Already Replaced Thermocouple After replacing the thermocouple, it worked initially for at least a couple of minutes. Every gas appliance with a standing pilot that cycles on and off needs a thermocouple. The pilot light wont stay on. Family is warm, what more can you ask for? Williams Wall Furnace Pilot Light Won't Stay Lit­ tuxedo cat. This pilot light may not always stay lit, due to a variety of issues that may affect the gas supply or ignitor. If your furnace’s pilot light won’t stay on, the furnace won’t work. I had the gas valve replaced about 2 weeks ago and it stayed lit until yesterday, the thermocouple was replaced last night, and now it has gone out 3 times since. Yesterday, I replaced the thermocouple with a universal thermocouple and cleaned out the dust and soot from the burner area. Last night I replaced the thermocouple (TC), cleaned the screen, hooked it up and it still would not light. Does my thermocouple need replacing? The thermocouple tells the furnace controller that the pilot light is working. If you cannot get the pilot light on your Rheem furnace to light and stay lit, the most common problem is a bad thermocouple. The pilot on my Rheem furnace will not stay lit. If the thermocouple doesn't sense heat coming from the pilot light, it shuts off the gas to prevent a leak or dangerous buildup. Try Cleaning Off Your Thermocouple if Your Pilot Light Won’t Stay Lit. it's sounds like it's time to change out the gas valve. This device generates a small electric signal to keep the gas valve open when the pilot is on. Your furnace pilot won't turn on when it is defective or too far away. The job of the thermocouple is to determine whether or not the pilot light is lit. i have a williams wall furnace Model #25GV-A1-5T. The gas valve sends gas to the main burner(s), which is lit by the pilot light. I bought this place several months ago and trying out the furnace ('93 Rheem) at for the first time (~40 degrees this past week) but realized the pilot was out. Sunday, we ran out of hot water, I checked and found one of them not lit. First, inspect the flame. I have an older ruud furnace. Your furnace's thermocouple, if it works normally, checks to see whether the pilot light is on or off. Lv 6. try not to bend them close to the end where it attaches to the valve and at the pilot burner. It’s crucial that the end of your thermocouple (tip) is in the path of a good pilot flame. I can light it and depress the pilot switch for 2 minutes. It could simply be that the thermocouple is bent. The problem may be a genuine defect or it could be an issue with the sensor. Why Water Heater Pilot Light Won’t Stay Lit After Replacing Thermocouple? This is not a rare issue that most of the people can never understand. You can check to see if this is your problem by seeing whether or not your pilot light is staying on. If this still doesn’t solve your problem, you may want to consult a professional. If your home furnace's pilot light won't stay lit, it's possible that your thermocouple has failed and should be replaced. If after inspection you determine there is a carbon buildup on it, try cleaning it off. We had a man come out and fix our furnace, he replaced the thermocouple in it. 1 decade ago. When a pilot light won’t stay lit on your gas water heater, this is exactly what you can expect. BMitch ♦ 41.2k 13 13 gold badges 82 82 silver badges 188 188 bronze badges. the pilot won't stay lit after replacing the thermocouple. I hold the button down in excess of 3 minutes and as soon as you release, the pilot light goes out immediatly. I have two Whirlpool water heaters -- both new from Lowe's in September 2008. 0 1. I have a Gas Wall Heater and the pilot won't stay lit. Your furnace will still have a flame sensor, but it will be over the burner’s flame. Since the thermocouple directly allows the pilot light to get turned on it is most likely to remain on for a while. Even after trying to relight the pilot light, you still may experience it going off. When finished, the pilot should be lit and stay lit. It will stay lit after initial light, but will go out after furnace runs. Relevance. ©2006 Publications International, Ltd. To adjust the pilot flame, turn the adjustment screw on the gas line, as directed by the range manufacturer. If the pilot light is not working, the gas control valve will not open and you won’t get any heat. The tech found the new gas valve to have a fault, as it won't switch to "off", only pilot or on, but I don't think this has anything to do with the pilot going out. After installation, I also did the detergent test to make sure the gas connections are secure and not leaking. A faulty thermocouple may arbitrarily determine that the light is off when you want it on and vice versa. However, if you are facing such issues, there may be mainly two reasons for such. I have replaced the thermocouple to no avail. It’s not unusual for the thermocouple to collect carbon deposit buildup after a season of use. But, once I let go of the button, the pilot immediately goes out. If you have a direct ignition furnace, you won’t have a pilot light. Thermocouples. Troubleshooting this issue may be helpful in determining the source of the problem and helping users identify a potential resolution. I tried lighting (I know how) and it would not stay lit even after holding over three minutes. A couple of days go by, and as I'm changing the humidifier filter, I notice the pilot light is out once again. Pilot won't stay lit even after replacing thermocouple on bbq! It won't stay on. furnace gas pilot-light. The thermocouple and safety shutoff do double duty, since on burners that use a pilot flame the thermocouple senses the pilot flame and won't permit the gas valve to open if the pilot is not lit. Thermocouples detect pilot lights by sensing the heat they produce. This is a safety device that closes your gas valve when the pilot light goes out so gas doesn’t enter your home. Its a hydro flame rv furnace… it looks like the whole unit can easily be replaced, except for a pair of yellow wires leading from a sensor at the top of the furnace vent down to where the thermocouple attaches to the gas valve. M Oglesby. What's up? Answer Save. If it determines that the pilot light is off, it shuts down the flow of gas. furnace won't stay lit, just replaced the thermocouple? Your furnace’s thermocouple is a copper rod that sits next to your furnace burners.It’s often called the “flame sensor” because its job is to detect whether the pilot light is lit or not.If it can’t sense a flame from the pilot light, it prevents the gas valve from opening and … Why does this happen? If the pilot lights but won't stay lit, the thermocouple is probably bad. The flame looks perfect, nice and blue, the thermocouple gets glowing hot when attempting to light the pilot. This has happened before, and a new thermocouple always fixed the problem. But, sometimes, thermocouples wear out, then you may need replacing. Mechanic's Assistant: Just to clarify, what are the exact lights you're talking about? howdy! Take out the faulty thermocouple and thermopile and replace them with new ones. Thermocouple vs. Flame Sensor . The pilot light is still going out after the heat kicks off. 8 Answers. A thermocouple is typically used on a gas furnace with a standing pilot, recognizable by its small, continuously burning flame that you can see if you remove the access cover on the furnace's burner chamber. I replaced the thermocouple but after 30-45 seconds it goes out. So what’s the deal? Some common causes include issues with the thermocouple and pilot tube. If not, then you need to either clean or do a gas furnace thermocouple replacement. Here are 5 reasons why your pilot light won’t stay lit and how you can fix it. Don't try to adjust the mechanism or tamper with the gas line. After all, your thermocouple is sitting in direct flame its whole life. When a propane heater won’t stay lit, often what is happening is that the propane heater may sense that the flame is defective in some way, triggering the propane heater’s safety functions and causing it to shut off. share | improve this question | follow | edited Oct 29 '13 at 1:23. 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