If your furnace pilot light keeps going out, it’s likely you have a broken thermocouple in your gas furnace. The thermocouple is a rod that comes into physical contact with the flame in your system. When this component is not able to detect the flame, it will close the gas valve to prevent a gas leak in your home.
Thermocouple Malfunction It is positioned very close to the flame, and when lit, the pilot light tells the thermocouple to keep the gas line open. A thermocouple that is dirty or malfunctioning will often shut off your gas supply in error, causing the pilot light to go out and your furnace to stop working.
Also Know, how do I stop my pilot light going out? Pilot Light Instruction Guide:
- Turn off furnace, boiler, or water heater at thermostat or power switch.
- Locate the gas valve and turn knob from on or off (depending where it was) to pilot position.
- Hold down red button, which sends gas to the pilot burner.
- At the same time hold match to pilot burner.
Moreover, why will my pilot light on my furnace not stay lit?
If your furnace’s pilot light won’t stay on, the furnace won’t work. Some common causes include issues with the thermocouple and pilot tube. The thermocouple detects the pilot light via sensors. A faulty thermocouple may arbitrarily determine that the light is off when you want it on and vice versa.
Is the pilot light supposed to stay on in a gas furnace?
The color of a healthy pilot light flame can vary a bit depending on whether your furnace uses natural gas or propane as a fuel. If the pilot light is out, attempt to relight it. If the pilot light does not light or does not stay lit, then replace the thermocouple.
How do you know if you have 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.
Is it dangerous if your pilot light goes out?
Can a Pilot Light Outage Be Dangerous? The worry here is that when a pilot goes out, the gas valve that supplies the fuel for the pilot flame could still be pumping gas. This can mean a buildup of gas, and when the pilot is relit or relights itself it could result in a very serious explosion.
How much does it cost to replace a thermocouple?
Thermocouple Replacement – $20-$150 Calling a professional plumber to install a new thermocouple should only be up to $150. If you do the work yourself, you will only pay the price of the part which is about $20.
How do you reset the pilot light on a furnace?
Once the gas has had time to dissipate, turn the knob to “Pilot.” Then, hold down the “Reset” button and bring the flame of a long lighter close to the pilot light opening. This should light the furnace pilot light. Once you are sure the pilot light is on, release your pressure on the reset button.
What does it mean if the pilot light keeps going out?
Usually, a problem with the thermocouple causes the pilot light to go out. The thermocouple is the small copper rod that the pilot light hits. The thermocouple’s job is to shut a gas safety valve if the pilot light goes out. That’s important because gas is always being supplied to the pilot to keep the flame lit.
How do you know if your furnace pilot light is out?
The pilot gas line is a small metal tube below the burner assembly and distinctive by the slight upturn at the end. It will be apparent, if the pilot is lit, by the small blue flame burning at the end. If you do not see a small blue flame burning, the pilot light is out.
What does a thermocouple look like?
The thermocouple looks like a piece of metal tubing smaller than a soda straw. To find it, first locate the gas control box. This is the box that the main gas line enters, where you turn the gas on in the furnace. The other end of the thermocouple sits in the flame of the pilot light.
How much does it cost to replace a thermocouple on a furnace?
Cost to Replace a Thermocouple on a Furnace Replacing a thermocouple costs $150 to $250, mostly due to labor time. On older models without an ignitor, it checks to make sure your pilot light is lit. If it’s not, it’ll shut the gas off.
Can you fix a thermocouple?
A burned out or broken thermocouple should be replaced. To replace a thermocouple: Step 1: Unscrew the copper lead and the connection nut inside the threaded connection to the gas line. Step 2: Under the mounting bracket at the thermocouple tube, unscrew the bracket nut that holds the tube in place.
What causes a thermocouple to fail?
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.
How do you test a thermocouple?
Steps Locate the pilot light controls on the gas valve. Turn the pilot light on for 30 seconds. Release the button to see if the pilot light goes out. Turn off the gas supply to test the thermocouple again. Count to 20 and wait for the pilot light to go out. Listen for clicking near the gas valve.
Can you clean a thermocouple?
If the Thermocouple is faulty it will cause the unit to shut down. How to clean? Remove Thermocouple from pilot assembly, using steel wool or emery cloth to lightly clean the tip removing any soot or build up that might have accorded due to an improper pilot flame.
How long does a thermocouple last?
Thermocouples can last several years, but they don’t typically last as long as the furnace itself. If the pilot remains lit, but the main furnace doesn’t stay lit, it’s time to replace the thermocouple. Replacement thermocouples are in stock at most hardware and home improvement stores.