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.
How long does a gas fire thermocouple last?
Although thermocouples can last
several years
, they don't typically last as long as the furnace. It's time to replace the thermocouple if the main furnace doesn't stay lit. Most hardware and home improvement stores have replacements in stock.
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
.
Can thermocouple burn out?
The most common failure mode for thermocouples is for them to fail open, this is known as thermocouple burnout
. Burnout can result from a variety of reasons including the thermocouple experiencing a temperature in excess of that for which it was designed, metal fatigue, and oxidation.
How much should a plumber charge to replace a thermocouple?
If your thermocouple goes bad, there is only one thing to do: Replace it. If you hire a professional plumber to do this, it may cost
up to $200
total. This is another repair you may wish to attempt on your own. The part itself should only cost $20 or $30.
What are the symptoms of 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.
Can thermocouple be cleaned?
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 long do Thermopiles last?
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.
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 do I test a thermocouple?
Are thermocouples universal?
Universal thermocouples come in lengths from 15 to 36 inches
. An 18 or 24 inch will suffice for all residential water heaters using universal kits. Almost all older waters heaters and many of the newer style units with a sealed burner compartment and a viewing window will use this thermocouple.
Does length of thermocouple matter?
The length of a thermocouple has no effect on its measurement accuracy or its ability to transfer the signal to the instrument
. In other words, thermocouples do not experience “voltage drops” or power loss along its length as a high current power line might possess.
What causes a thermocouple to read high?
If your thermocouple is reading high, it could be because
your sensor is located too close to a heat source
. If your sensor is near a local heat source it could increase the temperature being measured as opposed to the position you wish to measure temperature.
What is upscale burnout?
Upscale burnout is
a small current that is applied the amplification block of a thermocouple input
. The current is offset by the zero and span adjustments. The purpose is to drive the reading fullscale if the thermocouple fails (burns out or connection is lost).
What do thermocouples do?
Thermocouples are sensors used to
measure temperature
. It is a device used inside a gas furnace in Kansas, to assist the pilot light in keeping your furnace running and safe. It works rather like a fail-safe to keep unburned gas from accumulating and burning, exploding or causing another type of health risk.
What does it mean when your pilot light keeps 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.
Why won't my pilot light stay lit on my gas furnace?
If your pilot light won't stay alight,
it might be the thermocouple
. Sometimes dust buildup collects on the thermocouple and blocks the sensor. Try cleaning the thermocouple and then relighting the pilot light. If it continues to go out, the thermocouple might need to be replaced.
Is it expensive to replace a 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.
How much is a thermocouple?
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.
How far should thermocouple be from pilot?
The pilot light should be replaced if it does not stay lit. Look at the pilot light's color if it's burning. A pilot flame with a yellow tip should be strong enough to cover
1/2 inch at the end of the thermocouple tip
.
Why does my gas logs keep going out?
Drip Loop:
moisture in the gas line can cause a failure in the drip loop
. This could be the reason why your fireplace won't stay lit. Moisture can dilute the natural gas, so you'll want to have a professional see if this is the problem at hand.
Can I use sandpaper to clean a thermocouple?
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.
Why does pilot keep going out on water heater?
Thermocouple Issues
If it senses that your water heater pilot light keeps going out, the thermocouple will shift off the gas supply to the heater. Over time, thermocouples can malfunction, accumulate dust buildup, or the device can get bent away from the pilot light's flame.
How do you clean a thermocouple sensor?
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 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.
How long should a kiln thermocouple last?
The temperature range in which it is used can have a huge impact on the life of the thermocouple. For example,
a thermocouple used at glass temperatures may last for over 1000 firings
where the same thermocouple used at cone 10 may only last for 20 firings.
