Question: What Causes A Thermocouple To Fail?

How long does a thermocouple last?

10 yearsMainly, the thermocouple lasts for 10 years.

But, when it fails, the pilot does not lit up and so the fireplace stops working.

So, a thermocouple is an important device in the functioning of a fireplace..

Can you clean a thermocouple?

The best way to clean your thermocouple is to use either a piece of steel wool or the coarse side of a sponge to gently clean off any soot or other remnants. You can use a pencil eraser to clean between the threads of the screw that connects the thermocouple to the control valve of your system.

How hard is it to change a thermocouple?

The No. 1 cause of pilot lights that won’t stay lit is a worn-out thermocouple. It’s easy to replace and a new one costs $5 to $10. Rather than trying to unfasten the thermocouple inside the water heater’s burning chamber, it’s easier to remove the whole burner and thermocouple assembly.

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.

Do thermocouples fail high?

If they are short circuited or open circuited they will produce no voltage. In general I would expect this to read low, though it should read the same as when it’s disconnected for the most part. Typically the fail completely, no reading.

What happens when a thermocouple goes bad?

This means that if the thermocouple goes bad, there is no way of detecting if the pilot light is burning or not. And when the pilot light goes out, you will not have hot water supply in your plumbing system. To test if the problem is with the thermocouple, try to relight the pilot.

What are the sources of errors in a thermocouple reading?

Six Common Causes for Thermocouple Temperature Measurement ErrorsSelecting the Wrong Type of Thermocouple on the Transmitter. … Problems Related to the Thermocouple Extension Wire. … Inherent Variations in Alloys. … Temperature Variations Around the Reference Junction Connection. … Thermocouple Grounded at More Than One Location.More items…•Feb 1, 2018

Do thermocouples wear out?

Like the other component parts in your furnace, the thermocouple can wear down over time, producing lower voltage than it should when heated. And the worst part is that you can have a bad thermocouple without even knowing. Therefore, inspecting and testing your thermocouple should be part of your furnace maintenance.

Is it dangerous if the pilot light goes out?

Can a Pilot Light Outage Be Dangerous? The worry here is that when a pilot goes out, the gas valve that supplies the fuel for the pilot flame could still be pumping gas. This can mean a buildup of gas, and when the pilot is relit or relights itself it could result in a very serious explosion.

How do you troubleshoot a thermocouple?

Importantly, always make sure the tip of the thermocouple is directly in the pilot flame. If the tip is in the flame, you have held the nob on the gas valve down for longer than a minute, the pilot flame is strong and steady, and the pilot still does not stay lit, then you likely have a problem with the gas valve.

Can you fix a thermocouple?

If the pilot remains lit, but the main furnace doesn’t stay lit, it’s time to replace the thermocouple. Replacement thermocouples are in stock at most hardware and home improvement stores. Because they come in different sizes, take your faulty thermocouple to the store with you so you can make a correct match.

Can a thermocouple work intermittently?

a safety device that has started to go bad, or has failed permanently. In this client’s case, the thermocouple was initially working intermittently, and then finally failed. … This allowed the gas to flow long enough to heat up the thermocouple and generate some electrical current flowing back to the gas valve.

What’s the difference between a thermopile and a thermocouple?

The main difference between Thermocouple and Thermopile is their method of measurement. The thermocouple is a thermoelectric instrument, while the thermopile is an instrument that modifies thermal energy into electrical output.

What does 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. (On most furnaces, it also houses the button that you hold open or push to relight the pilot.)

How much of a thermocouple should be in the flame?

about 1/2 inchThe flame should strong enough to cover about 1/2 inch at the end of the thermocouple tip. If the flame is too strong and not adjusted correctly, it will be blue and may make a hissing sound as the flame crosses the thermocouple.

Will a pilot stay lit with a bad thermocouple?

The job of the thermocouple is to keep the pilot lit. It does this by sending a tiny electric current to a sensor on the gas valve signaling the valve to stay open. … Nothing lasts forever, and when the thermocouple wears out, the pilot won’t stay lit and your appliance won’t work.

Can you bypass a thermocouple?

So if you want to bypass the thermocouple you have to get rid of the spring mechanism. You can bypass the spring mechanism by simply using a screwdriver to pop out the little e-clip and take the valve off and problem solved.

Why does my pilot keep going out?

1) Faulty Thermocouple. If your pilot light won’t stay lit, the thermocouple is very likely the culprit. … The thermocouple is the copper rod the pilot flame directly hits. Sometimes it’s referred to as the “flame sensor.” It’s a safety mechanism that shuts the gas off should the pilot go out.

How do you check if a thermocouple is working?

Place one test lead on the side of the thermocouple and the other to the end that screws into the gas valve. If the thermocouple has proper continuity, a small resistance reading should be visible on the multimeter. Many multimeters also indicate continuity with an audio alert.

How much does it cost to repair a thermocouple?

The thermocouple is an apparatus that senses whether the pilot light is lit and triggers the gas control valve. Repairs typically cost about $150 to have it done professionally, though a new thermocouple itself only costs about $20 on average.

Does polarity matter on a thermocouple?

Back to Thermocouples: The most common type is the K type thermocouple which uses chromel and alumel metal alloys for the two types of metal. Well, it turns out that most grades of chromel used in thermocouples. … It matters, because thermocouples are DC, so there is a polarity.