If the pilot light on your gas fireplace won’t stay lit, a very likely culprit is a component called a thermocouple. A thermocouple is a safety device and is a component of the ignition system. The thermocouple is a metal rod that sticks out right in front of the pilot itself. It senses if flame is present or not.

If you get dust in the pilot assembly and the pilot needs to be cleaned out, it produces a “lazy” flame, which will be disturbed by the draught of the main burners. The flame lifts away from the thermocouple and causes the temperature on the tip of the thermocouple to drop. This, in turn, makes the gas valve shut off.

Often a gas fireplace has a millivolt generator which is in the path of the pilot flame. It is about the size of an AA battery and is wired to the switch and gas valve. If the millivolt generator is old and weak, or if the pilot flame is weak and wavering, the main burner will go on and off.

Is it expensive to replace a thermocouple? Thermocouple Replacement – $20-$150 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.

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.

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.

We recommend replacing these thermocouples every one or two years. When we move up the temperature scale above 1200°F, and particularly into the 1500° to 1800°F range, life expectancy of the Type K thermocouple drops off. Elements at this temperature tend to show signs of deterioration in the 6-to-12-month time frame.

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.

To bypass the thermocouple: Move the tilts switch wire aside. Remove your thermocouple from the heater using an 8mm wrench. The valve is the part that pushes in and out with your thermocouple.

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.

The main difference between Thermocouple and Thermopile is that the Thermocouple is a thermoelectric device and Thermopile is a device that converts thermal energy into electrical energy. Thermocouples are a widely used type of temperature sensor.

Watch out: thermopiles and thermocouples are not interchangeable. When replacing a temperature sensing device like a thermocouple or thermopile, you should be sure to purchase the proper part.

Both Thermocouples and Thermopiles follow the same principles of thermoelectricity (also known as the seebeck effect). However the main difference between the both of them is that a Thermocouple is a thermoelectric device, whereas a thermopile is a device that converts thermal energy into electrical energy.

Thermopile sensors don’t have a specific life expectancy or degradation rate. As long as they are used correctly and maintained properly, thermopiles can last for years or even decades and remain in good working condition. The key is typically to just avoid damaging or contaminating the sensor surface.

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.

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. Then unfasten the three nuts that hold the thermocouple and the two gas tubes to the valve.

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.