How can I tell if the 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.

Will the pilot light stay lit if the thermocouple is bad?

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 do I know if my thermocouple is thermopile or bad?

If your thermocouple is still in good condition, you should be able to read 25 millivolts of voltage or higher, but if it reads less than 25 millivolts, your thermocouple needs to be replaced.

Is the thermocouple supposed to be red hot?

The flame has to envelop the upper 1/2″ to 3/8″ of the thermocouple and the tip should glow a “dull red”. If the flame is adjusted to a sharp flame, it will glow “cherry red” this will cause the tip to be welded and eventually the thermocouple will fail.

Should thermocouple be in pilot flame?

The pilot flame should touch the thermocouple at a specific level. If the flame is blue and weak, and barely reaches the thermocouple, it needs to be stronger. If it extends well above the thermocouple, it’s too strong.

How long should a thermocouple last?

How to Tell if You Have a Bad Thermocouple? Thermocouples can last up to 10 years if properly installed and maintained, while furnaces can last 15-20 years, although either may wear out sooner in multifamily units.

Why does my pilot light keep going out after replacing thermocouple?

If your water heater pilot won’t stay lit even after replacing the thermocouple, you most likely have a faulty gas control valve. It is a sign that the valve is failing to open and allow gas to flow to the pilot. You could also be dealing with a tripped or faulty thermal switch.

How do I know if I need a new thermocouple?

A working thermocouple will give a reading of between 25 and 30 millimeters. If the reading is less than 25 millimeters, it should be replaced.

Can you clean a thermocouple?

Yes, you can clean a thermocouple, but the task must be done with a light touch. Remove the thermocouple from the process assembly, using a steel wool or emery cloth, lightly clean the tip removing any build up.

How tight should a thermocouple connection be?

Proper tightness should be finger tight plus ΒΌ turn. Inspect thermocouple to ensure that it is fully engaged into pilot bracket. Adjust tip of thermocouple to be fully engulfed by pilot flame.

What should a thermocouple read?

The reading should be between 25 and 30. Anything under or hovering around the 20 millivolts mark means the thermocouple needs to be replaced. Discretion should be used if the reading is between 21 and 25.

Can a thermocouple get too hot?

If the back end of your thermocouple bulb gets constantly overheated, it will fail. With excessive back pressure coming from the burner ports, thermocouples can get burned up quickly.

Why will my gas logs not stay lit?

The thermocouple and thermopile are the two most common reasons why a gas fireplace won’t stay lit. However, there are other possibilities out there. Another common culprit is incorrect gas pressure. As the seasons pass, you may find that your gas pressure drops below where it needs to be.

Can you bypass a thermocouple?

Realistically, you have just disabled the thermocouple, but you can also reach in and unclip it from its holding bracket where it meets the pilot light. In most cases it will be held on with a gravity clip, but some are held on with a screw that must be removed with a small screwdriver.

Why is my pilot light going out?

A faulty, misaligned, dirty, or damaged thermocouple is often the culprit behind your pilot light going out. The thermocouple is an automatic safety shutoff device that prevents the gas valve from opening if the pilot light is out.

Does gas leak if pilot light goes out?

If the pilot light goes out on a storage or instantaneous hot water heater, space heater or a ducted heater, you will not have a gas leak. This is because all modern gas appliances with pilot lights have a fail-safe device that closes off the gas to the appliance in the case when the pilot may go out.

How do you test a thermocouple?

Quote from the video:
Quote from Youtube video: If I take my wire and attach it to anywhere along the sheets of the probe. I attached to the sheath and I'm getting continuity this is a grounded thermocouple if this was an ungrounded thermocouple.

How do you fix a pilot light that keeps going out?

If it’s filthy shut your gas off so that the unit can cool down, then gently clean it by carefully rubbing it with fine grain sandpaper. When you’re done, simply turn the gas back on and light the pilot again. If dirt or grime was the issue, your light shouldn’t go out again!

How do you clean a dirty 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.

Will the gas company light My pilot?

Absolutely! We can send a gas service technician to light your pilot, and conduct a gas safety check of your gas fireplace or any other gas appliance to ensure your safety.