Why does thermocouple fail

Why does this happen? Of course, if you want to make sure the job is done right with the least amount of risk, contact experienced professionals at Hot Point for furnace repairs ASAP. Pilot light won't stay on? Read on for reasons why, and what you can do to fix it. The thermocouple is the copper rod the pilot flame directly hits. Sometimes it's referred to as the "flame sensor. If the thermocouple fails to shut off the gas, all the gas flowing through the furnace could get into your home.

The thermocouple safeguards against a catastrophic buildup of gas. First off, grab a flashlight and a screwdriver before inspecting your furnace. You'll have to remove the cover, and chances are the lighting won't be working in your favor. The only thing more frustrating than a busted furnace is the hundred trips to the garage for tools when you're trying to fix it.

For safety's sake, shut off power to the furnace by switching the breaker to the off position, and close the gas valve. The thermocouple isn't too difficult to find. Locate the pilot light and look for the tip of a copper rod very nearby.

That's the thermocouple. If you're having trouble locating the pilot or thermocouple, double-check to make sure your unit actually has a standing pilot light. Standing pilot lights are common in older furnaces, but many newer furnaces have intermittent pilot lights or hot surface igniters. In these systems, the pilot will only light in the case of hot surface igniters, the igniter surface heats when the thermostat makes a command for heat.

No matter the pilot configuration, the thermocouple will be near the burners—look for a removable metal rod nearby. Locate the copper rod near the burners. This is the thermocouple. If you look very closely, you'll find the thermocouple tucked in behind the burners.

The thermocouple needs to detect the flame, otherwise it will shut the gas valve, and your furnace will not function correctly. A malfunctioning thermocouple can lead to incorrect measurements and create big problems. Thermocouples are built to be resilient, but there are a few factors that can cause thermocouple failure. A good thermocouple is going to be used, and that can lead to metal fatigue. Changes in temperature can cause regular expansion and contraction in metal, which will cause thermocouples to weaken over time.

Count to 20 and wait for the pilot light to go out. Listen for clicking near the gas valve. How much does it cost to replace a thermocouple? What does a thermocouple look like? The thermocouple looks like a piece of metal tubing smaller than a soda straw. To find it, first locate the gas control box.

This is the box that the main gas line enters, where you turn the gas on in the furnace. The other end of the thermocouple sits in the flame of the pilot light. Does the length of a thermocouple matter? The length of a thermocouple has no effect on its measurement accuracy or its ability to transfer the signal to the instrument.

Are thermocouples universal? Universal Thermocouples. Universal thermocouples, as the name implies work on most water heaters. They are available online and in home supply stores for a reasonable cost.

The length and the thread type are the two concerns when purchasing one. Should a thermocouple be in the flame? Typically the thermocouple sensor is mounted right in the flame of the pilot light on gas fired heating equipment. But not all of these systems use a thermocouple. Some gas fired heating equipment relies on an electronic ignition to ignite the flame. Those devices generally will not use a thermocouple. Can a thermocouple leak gas? Without a thermocouple, it will seep tiny bits of gas into the combustion chamber of the device.

In a few hours, it can leak enough gas for a small explosion, probably just enough to shorten your eyebrows.