What causes thermocouples to go bad?

The presence of oxygen causes a reaction in the thermocouple that can wear down the part and make the wires become thinner and more brittle. Oxidation can be caused by a small amount of oxygen making its way into a sealed environment and reacting with the pure metal of the thermocouple.

Do thermocouples wear out?

Nothing lasts forever, and when the thermocouple wears out, the pilot won’t stay lit and your appliance won’t work. The pilot can go out for a number of other reasons, however, so if you’re having trouble getting the pilot to stay lit, the thermocouple may not be at fault.

How much does it cost to replace thermocouple?

It costs $150 to $250 to replace a thermocouple. It checks to make sure the pilot light is on. It will shut the gas off if it’s not.

Do thermocouples degrade over time?

Aging is a phenomenon that results in higher-than-accurate temperature readings, while drift results in lower-than-accurate readings. While all type K thermocouples experience aging and drift, best practices can minimize the risks and prolong thermocouple life.

How do I test a thermocouple?

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 do you know when to replace 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.

What happens if a thermocouple fails?

Normally when the thermocouple malfunctions or isn’t working, it simply shuts off the gas to your heater. This is important, particularly if the pilot light is out, because it prevents harmful gas from leaking into your home.

Do magnets affect thermocouples?

Faraday’s Law describes the phenomenon where moving an electrical conductor through a magnetic field results in the generation of electrical potential. The same effect can create voltage in thermocouple wires, especially if the wires are aligned perpendicular to a changing field.

Can a thermocouple drift?

Thermocouple drift is the potential for thermocouples to lose accuracy over time, moving in a positive direction. Thermocouple drift is more common when a thermocouple has been operating at higher temperatures for a prolonged period.

Can a thermocouple be repaired?

Thermocouples are designed to detect a pilot light’s loss of heat and close the gas valve to prevent a gas leak. Replacing a thermocouple is a relatively easy fix that can take less than two hours.

Are thermocouples universal?

Commercial thermocouples are interchangeable, economical, and supplied with standard connectors. Unlike most other temperature measurement devices, external form of excitation is not required for thermocouples because they are self-powered.

Can a thermocouple leak gas?

In a few hours, it can leak enough gas for a small explosion, probably just enough to shorten your eyebrows. If you were on vacation in Tahiti for a month and there is no circulation, enough gas could build up to some serious damage to homes and humans.

Should a thermocouple be in the flame?

The 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.

Can thermocouple wire be soldered?

Thermocouple materials are not solderable. It is possible to surround the thermocouple wire (encapsulate it) with solder but you cannot make a metallurgical bond to it. It is important to note that even if you could solder the two wires back together the thermocouple still will not work.

Can you cut thermocouple wire?

On the flip side, you can cut thermocouples down to a shorter length if you require that as well. Just make sure to cut the size you want out of the side with the actual sensing area on it.

Should the pilot light be touching the thermocouple?

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.

Why is my pilot light orange?

If your pilot light’s flame is orange or yellow, it is burning inefficiently due to a lack of oxygen. The thermocouple should sense when this happens because the heat from the flame will not be as hot as it should be.

How do 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.

Why is my pilot light flame yellow?

The most common reason why a pilot light would start to burn yellow is that the air intake valve to the pilot light is clogged with dirt. When this happens, air will be blocked to the flame and it will suffer from incomplete combustion (causing the yellow color).

Why does my pilot light flicker?

The pilot light needs air to burn, but not too much nor too little. Too much air, in the form of a draft, will cause the pilot to flicker and may blow it out. The draft may be coming from under a door or through a poorly-sealed window, or the draft may be intermittent, occurring only when a door or window is open.

Why is my pilot light flame too high?

So, if your pilot light flame also tends to be too high, ensure that your fireplace doesn’t have a button to bring the flame up or downward. If there’s no such button, adjust a screw on the fireplace. Turning it clockwise will reduce the fire whilst moving the opposite direction will raise it.

Is it OK to leave pilot light on gas fireplace overnight?

Is it safe to leave the pilot light on all the time? Generally speaking, it is safe to leave your continuous pilot light on at all times, assuming it stays lit (more on this in a moment). While it does cost more to keep your pilot light on in between uses, it can actually have some benefits to your system.