Once you've located the thermocouple, do a visual inspection. You're looking for a few things. The first is signs of contamination on the tube, which can include discoloration, cracks, or pinholes.
To figure out if your thermocouple is dirty, look at its tip. If you notice the tip is covered with a layer of soot, this means it needs to be cleaned as soon as possible. If you ignore this, you'll start having problems with the pilot light staying lit on a consistent basis.
Clean the Thermocouple: Use a brush or compressed air to remove any debris or dust on the thermocouple. A soft-bristled brush works well for this. Handle with Care: Be gentle during cleaning to avoid damage.
No. If the thermocouple is bad, the system sees the failure as a pilot light gone out, and shuts off the gas.
If the pilot flame ignites but goes out after you release the gas control knob, the cause may be a dirty or defective thermocouple. If the gas is on but the flame will not ignite at all, a pilot tube obstruction is the most likely issue. Remove the pilot tube from the gas valve and spray compressed air to clear it.
Signs of Physical Damage on the Thermocouple
If you can access the thermocouple, look for visible signs of wear and tear, such as bends, kinks, or discoloration. These issues can prevent it from working properly, and you'll need a furnace thermocouple replacement.
Overheating: Each thermocouple is designed to operate within a certain temperature range. Operating beyond this range can damage the thermocouple's materials, causing them to degrade faster than normal. Contamination: Exposure to harmful chemicals or debris can affect the thermocouple's performance.
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.
Cleaning the thermocouple
You can use Emery cloth sandpaper to gently clean any debris or build-up from the end of the thermocouple. If present, you should also clean off any corrosion where the power wire connects to the thermocouple terminal.
Common reasons include a nearby draft, dirt buildup, or a malfunctioning thermocouple. Another pilot light drawback is energy waste. Since the pilot light needs to remain active, your furnace is always consuming some gas. It's not a lot—usually just a few therms of gas a month–but that obviously adds up over time.
Thermocouples are relatively affordable components, typically ranging from $10 to $30, depending on the brand and quality. However, keep in mind that DIY replacement requires knowledge of furnace systems and gas connections, and improper installation can lead to safety hazards.
Blow away Debris
Use short bursts of compressed air to blow dust and debris off the first 1⁄4 inch of the thermocouple's tip. Ensure no debris falls into the pilot assembly.
Temperature sensor and thermocouple errors can be caused by various factors, such as mechanical damage due to physical stress, abrasion, or corrosion; electrical interference from nearby sources of electromagnetic radiation; wiring problems like loose, broken, or mismatched connections; calibration issues that cause ...
Here at Boss Plumbing, we highly recommend you not try to replace the thermocouple on your water heater yourself. Though not a highly complex water heater repair, it nevertheless does involve the use of gas. Thus, if you are unsure about what you are doing, one small mistake could lead to a disaster.
Failed Thermocouple Symptoms
The first is signs of contamination on the tube, which can include discoloration, cracks, or pinholes. Next, check the wiring for any signs of wear or corrosion like missing insulation or bare wire.
Standard Thermocouples: Typically last 1-3 years in industrial applications. Specialized Thermocouples: Can last 5-10 years or longer in controlled environments.
How often should a thermocouple be calibrated? We recommend that thermocouples are calibrated once every 12 months to ensure they maintain accurate, repeatable and high-quality temperature measurements.
If you try to relight a pilot light and the thermocouple is bent in a way that causes it to not make contact with the pilot light, the flame will instantly go out when you release the pilot control knob since the probe won't detect the heat from the flame.
Symptoms Pilot won't light. Pilot lights but burner won't. System lights, but goes out after a while.
While both devices are crucial for temperature measurement and control, their specific applications and capabilities vary. Thermocouples are primarily used for direct temperature measurement and safety controls, whereas thermopiles are preferred for applications requiring higher sensitivity and voltage output.
There's really just one telltale sign of letting you know when the thermocouple isn't working, and that's when the pilot light won't stay lit. If you experience this problem, it's important to have your thermocouple assessed as soon as possible.
A thermocouple is a device consisting of 2 different conductors that produce a voltage proportional to a temperature difference between either end of the pair of conductors. There are many types of thermocouples, with varying types of conductors and probe designs.
The Pilot Tube Is Clogged
Another common reason that a pilot light won't stay lit is because of a clogged pilot tube. Gas travels through the pilot tube to keep the pilot light burning. If the tube is completely clogged, no gas will flow, and you won't get the pilot to ignite at all.