This … What to Do if a Gas Furnace Pilot Light ... What to Do if a Gas Furnace Pilot Light Won't Stay Lit. Thermocouple and pilot tube burner in gas furnace Step 3 – Clean Dirty Thermocouple: If the thermocouple is NOT bent and is aligned correctly, you may have a clogged or dirty thermocouple. I show how to bench test a thermocouple for a gas furnace using a multimeter. First take a wrench and slightly make a tightening adjustment at the base of the thermocouple. HOME The tip of the thermocouple is positioned in the flame, keeping the tip heated at all times. It is high in calcium and magnesium, so limescale can create problems with plumbing and appliances. Diagnosing a Thermocouple Problem If your pilot light ignites but won’t stay lit, then the problem is most likely related to your thermocouple , a metal sensor (about the size and shape of a sharpened pencil) that heats up by direct contact with the pilot light’s flame, telling your gas valve that the pilot light is lit so it’s safe to open the valve to let gas flow. Take the thermocouple to a hardware store for a replacement which is the same size on each end and same length or longer. Please try your search again later. Be sure you use the exact furnace details so you get the correct size replacement for your furnace. Check to see if you're getting 24 VAC at the terminals on the gas valve. To be sure the problem is coming from the gas furnace thermocouple and not the pilot, clean the pilot valve out with a fine wire and be sure that the outlet is not clogged from residue or build-up. Questions of a Do It Yourself nature should be A noisy boiler is often caused by “Kettling”, which is a build up … That is more of a catch-all time frame for thermocouples which may heat up (and thus generate current) more slowly. I suspected the thermocouple and replaced it, but this didn't fix the problem. Leave a Review, FIXED PRICE REPAIRS Burnham Boilers have been around for a long time and are still one of the top boilers today. Burnham Holiday Boilers: how to remove and clean burners. Once this is complete go ahead and remove the pilot cover which will reveal two upright posts, one is the gas line for the pilot and the other is your thermocouple. How to Install a Gas Shut Off Valve in a... How to Install a Gas Shut Off Valve in a Gas Furnace. Website operating Thermocouples are essential for displaying the temperature especially in a residential environment. A reading of less than 25 millivolts indicates that the thermocouple is bad and needs to be replaced. Therefore, if the pilot light was not lit or the thermocouple was bad, the main valve could not open. You may freely link This heating can cause the dissimilar metals inside the thermocouple to break apart temporarily dropping the output voltage to zero. If you are wondering, Intermittent thermocouple problems can occur if the pilot flame heats the lower 1/3 of the thermocouple. 12 MONTH GUARANTEE. Working with electrical systems is dangerous and may cause damage to yourself and your home if handled incorrectly. People also ask, what happens when a thermocouple goes bad? Common problems that may occur with it can sometimes be fixed by a layman with an idea of the mechanics behind it. This heating can cause the dissimilar metals inside the thermocouple to break apart temporarily dropping the output voltage to zero. Once you have located the thermocouple, do a visual inspection. Older boilers may have a permanent pilot light which needs to stay lit in order to light the larger burner within your boiler. If the pilot does not ignite, turn the gas switch off again, and wait the few minutes for gas dispersion. Your furnace pilot won't turn on when it is defective or too far away. 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. Problems with Furnace Thermocouples Generally, when you learn what a furnace thermocouple is and what it does, you’re trying to fix your furnace because it’s not coming on. The tip of the thermocouple is called the hot junction and is where the two dissimilar metals join. The thermocouple has nothing to do with the boiler short cycling on the low water cut off. You can find a gas furnace thermocouple replacement at any good hardware store, or even on some on-line stores. Therefore, inspecting and testing your thermocouple should be part of your furnace maintenance. In fact, the problems that affect gas furnaces typically involve the furnace's thermocouple, the pilot light, or some component of the electrical system. PRIVACY POLICY All our plumbing repairs come with a 12 month no-hassle guarantee for ... See our Common Service Questions here and check out our helpful home resources centre. A common culprit for this fault on Baxi boilers is a lack of pressure. © 2001-2019 PEACE OF MIND PLUMBING Ltd. All rights reserved | Owned & Operated by Peace of Mind Plumbing Ltd. Relax…with us, you’ll know the full price BEFORE we start so there’s no guesswork or nasty surprises. NOTE: It is the temperature difference between the cold and hot junction that creates the millivolts. suggestions. Or the thermocouple might be faulty, causing the gas supply to shut off. Make sure to handle the thermocouple with care. The thermocouple needs to detect the flame, otherwise it will shut the gas valve, and your furnace will not function correctly. Asides from leaks, there are other problems that can cause a boiler to lock out including fault codes: 110 (overheating), to 160 (a faulty fan) or even 166 (air pressure switch fault). As a result, the thermocouple can’t properly detect heat, or loss thereof. Noisy Boiler or Noisy Central Heating. A broken or burned out thermocouple won't detect the flame properly, effectively closing the gas valve until you replace it. A burned out or broken thermocouple should be replaced. If it does not light then you will then want to go ahead and unscrew the thermocouple with your wrench and remove it. Stop Turn the GAS COCK off and Call a … Thermocouples fail, and must be replaced periodically. If there is soot build up on your thermocouple, then the issue might be resolved by cleaning your thermocouple. CDN$11.99. discoloration, cracks, or pinholes. 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