How Do You Check If A Thermocouple Is Working?

How much does it cost to fix 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..

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.

How much should a plumber charge to replace a thermocouple?

Calling a professional plumber to install a new thermocouple should only be up to $150. If you do the work yourself, you will only pay the price of the part which is about $20.

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.

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.

How many volts does a thermocouple produce?

The normal millivolt output is 25 to 35 millivolts; on some, you may even get up to 35. The other part of this safety pilot system is the electromagnet (power unit). It is if you will the LOAD and we can say the thermocouple is the SOURCE.

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 u 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.

What is the output voltage of a thermocouple?

Voltage signal is small: The most common thermocouple types are J, K, and T. At room temperature, their voltage varies at 52 µV/°C, 41 µV/°C, and 41 µV/°C, respectively.

How do I know if my thermocouple is bad?

If you can’t get the flame to light at all, and you’re sure the gas is on, there’s probably an obstruction in the pilot tube. If the flame lights and goes out when you release the gas control knob after holding it in for the recommended 20 to 30 seconds, that’s the sign of a thermocouple malfunction.

How do you read a thermocouple with a multimeter?

Turn on the multimeter and select the ohms/resistance reading option. The multimeter should display a very small resistance in the order of a few ohms, if the thermocouple is fine.

What causes a thermocouple to fail?

Changes in temperature can cause regular expansion and contraction in metal, which will cause thermocouples to weaken over time. After enough time, metal fatigue can cause a thermocouple to break. … If thermocouples start to give out unusual readings, it may be suffering from metal fatigue.

Can I replace a thermocouple myself?

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.

What happens if a thermocouple is wired backwards?

If you accidentally reverse the polarity of the thermocouple lead wires, the measured temperature will be incorrect by the difference in temperature of the two ends of the leads.

What does it mean when the pilot light keeps going out?

Usually, a problem with the thermocouple causes the pilot light to go out. The thermocouple is the small copper rod that the pilot light hits. The thermocouple’s job is to shut a gas safety valve if the pilot light goes out. That’s important because gas is always being supplied to the pilot to keep the flame lit.

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.

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 do you adjust a thermocouple?

Adjusting the Thermocouple Correcting the first condition is a simple process. Simply shut off the gas, reach under the burner and push or pull the probe to reposition it. If the thermocouple is faulty, remove it by unscrewing it from the burner and pulling it out. Reverse the procedure to install a new one.

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.

How do you test a thermocouple continuity?

Check for continuity by using a multimeter set up to measure ohms. Connect the multimeter test leads to the 2 thermocouple leads (polarity doesn’t matter for this test) and if the meter reads 0 or open circuit, then at least one of the thermocouple leads are broken.