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.
What are the symptoms of a bad thermocouple on a furnace?
When the thermocouple is defective, even though the pilot light is burning, the main burner won’t light – no matter how cold it gets. The thermocouple looks like a piece of metal tubing smaller than a soda straw. To find it, first locate the gas control valve.
Can you clean a furnace thermocouple?
It’s easy to clean a furnace thermocouple, and all you need is a little elbow grease and an emery cloth. You won’t need any special solutions or tools for this job.
What happens when a thermocouple goes out?
If the appliance has a thermocouple, the problem may be a faulty thermocouple. The thermocouple, which operates as a safety device, turns the gas supply off when the pilot light goes out. When a thermocouple fails, the pilot light won’t stay lighted. A burned out or broken thermocouple should be replaced.
Can I replace a thermocouple myself?
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 much does it cost to replace a furnace thermocouple?
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.
What causes a thermocouple to go bad?
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. If thermocouples start to give out unusual readings, it may be suffering from metal fatigue.
How long should a thermocouple last?
In effect, new thermocouples were installed into contaminated tubes, causing the degradation of the sensors and generating greater than a 100°F shift in accuracy. In this scenario, thermocouple life, which should have been close to one year, was shortened to within a week.
How do you trick a thermocouple?
The thermocouple always thinks the pilot is not lit, even if it is. To get hot water, I have to light the pilot, then hold the match on the thermocouple to trick it into thinking the pilot light is touching it. Once it’s warm enough, I pull the match out and turn the knob from “Pilot” to “On”.
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.
Can you repair a thermocouple?
Thermocouples are designed to detect a pilot light’s loss of heat and close the gas valve to prevent a gas leak. Replacing a thermocouple is a relatively easy fix that can take less than two hours.
How much is a new 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.
What does a thermocouple do on a gas furnace?
Furnace thermocouple. A furnace thermocouple is a device on a standing pilot gas furnace that’s responsible for opening and closing the main gas line to your furnace. A slim, rod-shaped sensor sits in the path of your pilot flame where it collects and then transfers heat down via a flexible connector (wire or tube) to signal,…
What should the tip of a thermocouple look like?
It’s crucial that the end of your thermocouple (tip) is in the path of a good pilot flame. First, inspect the flame. It should have a yellow tip and cover the tip of the thermocouple. The idea is to make that sensor portion really hot. If it is short and blue, then it is too weak.
How to fix a broken thermocouple?
Carefully push or bend it into place, as it may have been bumped out of alignment during attempted repairs. If you’ve tested the thermocouple, and the flame didn’t stay lit, then it’s time to clean it. Carefully clean the end (sensor part) with a small wire brush, or ideally an emery cloth. You can even use the end of a knife or smooth sand paper.
Is your furnace thermocouple to blame for Burnout problems?
Usually a furnace thermocouple is to blame when you can’t keep a pilot lit or if it is lit, the burners aren’t firing. Whatever the case, you either have to make some adjustments, do some cleaning, or do a replacement. Let’s take a quick look at how you might troubleshoot and fix a furnace thermocouple.
