Thermocouple's indicating end not fully secured into the gas valve. I could replace the thermocouple again, but now I cannot find one with that extra wire thing. What is a common failure rate in postal voting? I have had the thermocouple replaced and the gas oriface cleaned. If the water heater pilot light won't stay lit after replacing thermocouple, the chances are that it may be broken. Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. Main Hearth Forums. Apologies for the delay. They are dependent on one another, totally. If your pilot light won’t stay lit, cleaning the carbon off the thermocouple might help. I know it seems strange but I default to thinking the TC is always the problem. Lately it has started acting up. I have had to replace my thermocoupler 3 times in 4 years the last one only lasted 3 months can you recommend a brand name and why is this continuing to happen My gas boiler is 35 years old and in good condition The boiler is a Hydrotherm. Personally, I would try the sandpaper first and see what happens, and maybe spend the $15 on a cheap multimeter (or borrow one from a friend). Oct 19, 2011 4 NH Lakes Region. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Replaced the thermocouple on my elderly Williams dual wall heater a couple of years ago. Inadequate combustion air - very dangerous, can be fatal, Dirt on the equipment burner, thermocouple, connections, wiring, Dirt or debris or insects (spiders) clogging the pilot orifice or pilot light gas tube. I suspected the thermocouple and replaced it, but this didn't fix the problem. Issue #1: Bad thermocouple A furnace thermocouple is a safety feature that regulates gas flow to your system based on whether or not the pilot light is on. Is there a way to tell (I dont have a multimeter)? Thermocouples on heating appliances: this article describes thermocouples, safety devices used on gas fired heating equipment. F. ferenc5 New Member. Took it apart, removed dead bird, put it back together furnace fired up. Will pilot stay lit if thermocouple is bad? Sometimes it's referred to as the "flame sensor." Sounds like the gas valve is not opening to light the burner. Thank you. Do the violins imitate equal temperament when accompanying the piano? After years of use, your thermocouple may have a buildup of carbon deposit, which affects its ability to function. Vacuum, inert, reducing atmospheres, hot processes, eg: plastic & resin mfg. Dirt and grime can build up and block proper flow of gas. We also provide an ARTICLE INDEX for this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. Therefore, most modern appliances do not have a pilot light. A bad thermocouple itself can prevent a gas furnace or boiler from working - if you can light the flame at the pilot manually but then the flame goes out when you release the manual gas @PlatinumGoose i thought that the TC isn't about keeping the pilot on - its also about the voltage communicated. Did I get a bad thermocouple or is there something else going on? But indeed, the pilot is on and the TC is hot, so it doesn't seem obviously that. The thermocouple achieves this thanks to the probe. But do not nick, kink, nor make sharp bends in the tubing. We use cookies to give you the best possible experience on our website. What legal procedures apply to the impeachment? Would have some dust in it additionally that isn't allowing it to stay … Does the pilot flame of a gas furnace stay on for the duration of a heating cycle? Damaged Thermocouple. If you are really convinced that the thermocouple is causing the pilot to turn off, you can try rubbing it with some sand paper or one of those green 3M scrubbers. The thermocouple connecting tubing has been mechanically damaged, crimped, cut or nicked. Don't confuse a thermocouple (discussed here) with a different type of temperature sensor, solid-state THERMISTORS used in thermostats. Customarily when the pilot is not going to stay on the thermocouple is bad. I'm not aware of any thermocouple on gas appliances that use a flare fitting. If your pilot light won't stay lit, the thermocouple is very likely the culprit. It’s designed to determine whether the pilot light is lit and then subsequently signals the gas valve to open. Would have some dust in it additionally that isn't allowing it to stay on. A bent, dirty, or damaged thermocouple could be the reason your water heater pilot won’t stay lit. Pilot won't stay lit beyond releasing the button to light it. This part senses when the pilot light is on using an electric current. Williams Wall Furnace Pilot Light Won't Stay Lit­ With the result of a blockage in the pilot tube, the Williams wall furnace pilot light won't stay lit. We often find this problem in southern climates where heating equipment may be installed outdoors or in a shelter exposed to wind. Our sketch at above left, illustrating a typical use of a thermopile, a type of thermocouple, in use at a gas boiler, is adapted from Weil McLain.[3]. That could be a few different things. Uber Member : Dec 9, 2009, 01:02 PM Try cleaning it. Furthermore, what causes a thermocouple to go bad? Is there a chance - without getting into too much repair costs - that the thermocouple isn't doing "its job" by signaling voltage so everything looks OK and I just need to replace the TC? That current is powered by the heat that comes from the pilot light. So after some troubleshooting it turned out to be a dead bird that had come down the flue and gotten lodged in the flue draft inducer fan preventing its squirrel cage from turning. If you have a gas water heater and the pilot light will not stay lit, it's most likely due to a failed thermocouple that will need to be replaced. i even cleaned off the tip of the old thermocouple and that ... i replaced the thermocouple, but the pilot won't stay lit. Something is loose inside, I think. Thermopiles are used to measure temperature without having to contact the object being measured. Pilot won't stay lit. If the thermocouple is bent: A bent thermocouple might not be close enough to the flame to sense it and provide gas. The thermocouple is a small metal sensor or rod that is situated directly in front of the pilot light. Damaged Thermocouple. Replaced thermocouple and still had a problem staying lit. After years of use, your thermocouple may have a buildup of carbon deposit, which affects its ability to function. That is a less common problem in my experience.Lastly, it's possible that the defect is in a gas flow or clog problem in the pilot light itself. But not all of these systems use a thermocouple. I've used this furnace for over 15 years without replacing the thermocouple. The pilot won't stay lit on my furnace, when I release the button it just goes out. TonyIt would be unusual to get a batch of bad thermocouples such that you have to keep replacing them because of an inherent defect in the thermocouple itself. How does one wipe clean and oil the chain? A bad replacement thermocouple or thermocouple tubing that was bent, kinked, damaged during installation, Thermocouple not properly connected at the control, e.g. Then you can let go of the button. It’s designed to determine whether the pilot light is lit and then subsequently signals the gas valve to open. If the thermocouple if new, then the valve is faulty, not staying open to present the flame. If you can manage to get the pilot light lit for just a moment, inspect the flame. Nothing lasts forever, and when the thermocouple wears out, the pilot won’t stay lit and your appliance won’t work. Photo at left: red arrows indicate the thermocouple tubing and assembly; blue arrows indicate the pilot light tubing & assembly on a horribly rusted Holland brand gas furnace. Check for debris blockage right at the pilot light, inside the gas tube between the pilot light and the gas control valve, and using a fine wire (don't scratch or enlarge the orifice) try cleaning the orifice at the pilot light itself. Typically the gas control is pushed-in or held in a spring-loaded position to force gas through the pilot light assembly to permit manually lighting the pilot flame. Everything looks good and I too think it could be the gas valve that is gone bad. Thermocouples. 4. This article explains what a thermocouple (or thermopile) is, how these devices work, where they are installed, and what goes wrong with thermocouples. Thread starter ferenc5; Start date Nov 27, 2012; Forums. In that case, the TC is usually a reasonable bet. If you have a furnace with a pilot light, then you will have a thermocouple. Also I am assuming you do … Pilot won't stay lit. Not unless they were all made by the same company in the same batch.When I have run into this recurrent thermocouple problem before it has usually been traced to a problem at one of the two ends of the thermocouple.One end, at the pilot, needs to be located exactly properly, mounted and placed in the flame of the pilot light.The other problem at the other end of the thermocouple is more subtle.