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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 a thermocouple be bad if the pilot stays lit?
NO. The purpose of the thermocouple is shut off all gas flow if the pilot light goes out. The thermocouple is a basic safety feature on anything that uses a pilot light. If the pilot light goes out, the thermocouple will turn off the gas and prevent it from accumulating which can be dangerous or deadly.
How long do thermocouples 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.
What causes thermocouples to go bad?
METAL FATIGUE Like everything, thermocouples can’t stay new forever. 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.
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 do you bypass a thermocouple?
To bypass the thermocouple: Move the tilts switch wire aside. Remove your thermocouple from the heater using an 8mm wrench. Pull the valve housing aside using your 13mm socket wrench. Remove the valve using your pliers. Put your thermocouple back into position.
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.
Can a thermocouple work intermittently?
In electrical circuits, the most unreliable points are electrical connections. So, if in a thermocouple circuit any of the connections suffer from corrosion or lack of intimate metal-to-metal contact, intermittent operation will result.
How do you clear a pilot tube obstruction?
How to Fix a Plugged Pilot Hole on a Water Heater Remove the cover plate at the bottom of the water heater. Turn the gas control to the “Off” position. Locate the pilot tube. Clean the pilot hole by brushing it with a stiff wire brush. Screw the bracket back onto the valve and turn on the gas.
How much does a thermocouple cost?
It costs $150 to $250 to replace a thermocouple. It checks to make sure the pilot light is on.
How do you clean a thermocouple on a gas fireplace?
How to Clean the Thermocouple in a Gas Fireplace Turn off the fireplace gas valve and remove the front panel from the fireplace. Find the thermocouple, which is located next to the pilot light and looks like a small straight pipe. Use a can of compressed air to gently blow away any dust and dirt from the thermocouple.
What does it mean when your pilot light won’t stay lit?
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.
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 you replace a thermopile with a thermocouple?
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.
How many volts does a thermocouple produce?
A single thermocouple (C Type) is used for a standing pilot system and generally produces around 30 millivolts. This voltage is used by the gas valve to keep the pilot valve solenoid internal to the main gas valve open.
How do I know if I need a new 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.
What is the most common thermocouple failure mode?
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?
Hot water heater repair cost Service Average cost to repair Leak repairs $100 – $1,000 Pilot light replacement $50 – $200 Pressure relief valve replacement $50 – $300 Thermocouple replacement $100 – $325.
Is a flame sensor and thermocouple the same thing?
People tend to use the terms “flame sensor” and “thermocouple” interchangeably. In truth, while they basically perform the same job, they’re not the same thing. If your furnace uses an electronic controller, it’s got a flame sensor. Thermocouples are used on standing pilot furnaces that have pilot lights.
What do you do if your pilot light won’t light?
You need to turn the valve to the off position for at least three minutes. Once you have had the valve at off for a few minutes, switch it over to pilot setting. You will need a match that is lit. Hold it to the pilot opening and push the reset button on your pilot control.
How do you clean a thermocouple pilot light?
How to Clean a Pilot Light Cut off the gas to your furnace. Remove the pilot light and thermocouple assembly. Use your pliers or wrench to remove the pilot light and thermocouple from the bracket. Using the wire brush, brush away the carbon buildup and soot from both components.
