Table of Contents
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.
How long do furnace thermocouples last?
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.
Is it expensive to replace 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.
How do I know if my thermocouple is bad on my furnace?
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.
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.
What causes a thermocouple to fail?
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.
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.
What do I do if my pilot light keeps going out?
Once The Flame Is Lit, Turn Gas Control Valve to “On” Once the pilot light is ignited, you can release the reset button after 30 seconds and turn the gas knob to the “On” position. At this time you should hear the main burner come on. Now your pilot light should hold a flame and hot water should be restored!.
What happens when thermocouple goes bad?
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.
Can a thermocouple be bad if the pilot stays lit?
The function of a thermocouple in a gas valve is to assure that an active pilot light is functioning properly to ignite any supply gas. If the thermocouple fails, for any reason, the gas flow must be shut down even if the pilot is properly lit. The function is termed a “Fail Safe” mode.
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.
Are thermocouples universal?
Honeywell, White Rodgers, and other manufacturers make universal replacement thermocouples, usually with a 30-millivolts (mV) rating for standing-pilot furnaces. Electronic flame sensors are much less universal, and you must find the exact part specified for your furnace model.
Can you bypass thermocouple on furnace?
Realistically, you have just disabled the thermocouple, but you can also reach in and unclip it from its holding bracket where it meets the pilot light. In most cases it will be held on with a gravity clip, but some are held on with a screw that must be removed with a small screwdriver.
Why is my furnace not staying lit?
Probably the most common issue when dealing with a furnace that will not stay lit or ignite consistently is a dirty flame sensor. The flame sensor acts as a communication vehicle with the circuit board and tells it when a flame is lit inside the furnace.
How do you check if a thermocouple is working?
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.
Why did my furnace pilot light go out?
The thermocouple on your heating system is a safety device that determines whether or not your furnace pilot light is lit. 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.
How much does it cost to fix a pilot light?
Pilot light replacement or lighting cost Water heater pilot light replacement costs $50 to $200. The pilot light produces a flame to ignite the gas burner. Plumbers charge $45 to $150 per hour to reignite the pilot light, and the task typically takes 1 hour or less.
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.
Can a thermocouple short out?
The temperature is converted by the controller or pyrometer. There are two wires connecting the thermocouple to the controller. If the lead wires touch at a bare spot where the insulation has worn off or is stripped back too much, they will short out.
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.
