Question: What Is A Thermocouple On A Water Heater?

How do you know if you have a bad thermocouple?

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 much does it cost to replace a thermocouple on a water heater?

Thermocouple – $20 to $150 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 do you clean a thermocouple on a water heater?

Clean the thermocouple – using the emery cloth sandpaper, sand the ends of the thermocouple and then give it a finishing touch with the lint-free cloth. Hopefully, you can get to the ends of the thermocouple without having to detach it from the assembly, but you may have to do that.

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What happens if you have a bad thermocouple?

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.

Will a pilot stay lit with a bad thermocouple?

What is a Thermocouple? A thermocouple senses the heat of the pilot and allows gas to flow to the burner. A bad thermocouple will shut off gas to both the pilot and the burner so the pilot light won’t stay lit.

How long does a thermocouple last?

All things considered, the question remains, “How long should my thermocouple last?” The answer to that question is that it depends on the application. In an ideal environment, that length of time can be indefinite.

Can I replace a thermocouple myself?

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.

Why does pilot not stay lit on water heater?

Lack of Combustible Air. Another reason your gas water heater pilot light won’t stay lit could be due to not having enough combustible air. Your water heater requires air to keep the pilot light burning. Otherwise, the flame goes out.

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

If the pilot light goes out, the thermocouple senses the drop in temperature and signals for the gas valve to close. If you have a faulty thermocouple is the most common reason that your pilot light is malfunctioning. Over time your water heater will collect dirt, dust and other kinds of debris.

Can I 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.

Can a thermocouple be too long?

The length of a thermocouple has no effect on its measurement accuracy or its ability to transfer the signal to the instrument. In reality the sensor can be inches or thousands of feet long and the accuracy will not be affected.

What do you do if your pilot light won’t stay lit?

How to Light Your Furnace’s Pilot

  1. Make sure the thermostat is in heat mode.
  2. Locate the pilot valve.
  3. Always turn the valve knob to the off position and make sure to wait at least several minutes for any residual gas to clear away.
  4. Get your match ready.
  5. Once the pilot stays lit, turn the pilot valve to the on position.

How do you check if a thermocouple is working?

If the thermocouple is working, you should be able to measure 30 to 40 millivolts of voltage at the connection end of the tube when the pilot flame is on. You can test this yourself using a multimeter, but you may need a helper to keep the pilot flame burning while you do it.

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What causes 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 you fix a thermocouple?

If the pilot lights but the flame goes out as soon as you release the button after holding it for 60 seconds, then the thermocouple is bad. It’s possible to replace the thermocouple without removing the burner assembly, and many repair people do this.

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