The flame sensor on your furnace requires occasional maintenance to perform its job correctly. Fortunately, you can perform this maintenance task by yourself. You just need the right tools and some know-how to complete the job.
As Elgin’s top-rated furnace company, our team at Leith Heating & Cooling developed a short guide to help you learn how to clean a furnace flame sensor. Discover how to safely maintain your sensor by reading more below.
How Your Furnace Flame Sensor Works
First, learn more about the flame sensor’s role in your furnace operations. The furnace flame sensor looks like a small, slender piece of metal. It conducts electricity to determine whether a flame is present in your furnace. When it detects a flame, it sends a signal to your furnace’s control board.
This signal directs your furnace to work when you need heat. However, a dirty flame sensor may not sense a flame’s presence. When this occurs, the sensor will signal for your whole furnace to stop working.
You might panic and wonder whether you should call a service technician to correct the problem. In most cases, you can remove and clean the sensor to make your furnace provide adequate heat again. If you’ve experienced the following issues, you might have a dirty flame sensor on your hands:
- Excess soot
- Short-cycling when your furnace has no other issues
- The burner light powering off soon after you switch your furnace on
- Occasional clicking sounds originating from your furnace
- Your furnace won’t work
How to Clean Furnace Flame Sensor
You can learn how to clean a furnace flame sensor in five simple steps. This maintenance task requires little time, effort, or money. If the problem persists, you may need a new flame sensor or a qualified technician to see if you have a more serious furnace problem.
#1 Purchase Cleaning Supplies
Before locating and cleaning the sensor, collect all the materials needed to complete the task. Flame sensors require specific cleaning materials for deep cleaning and damage prevention. Check your home for the following materials:
- Grit sandpaper or steel wool
- An appropriately sized screwdriver
- Paper towels or Emery cloths
If you don’t have these items, purchase them before continuing to the next step.
#2 Power the Furnace Off
Next, shut off the power supply. You should also shut off the gas if your furnace uses natural gas. You can do this by finding the appropriate switch on or around your furnace.
This switch may look like a toggle. If you can’t find the switch, locate your circuit breaker to power your furnace down. Remember that your thermostat has no control over whether or not your furnace connects to electric circuits.
This step prevents injury and other destructive accidents.
#3 Locate and Inspect the Sensor
You can locate a flame sensor near the burner assembly of most furnace models. It should appear as a tiny metal rod. If necessary, use a screwdriver to gently remove the screws that hold it in place.
Your sensor may have a cable connection. If so, you can easily remove the cable for easier inspection and cleaning. Once you’ve removed the sensor, inspect it for any damage.
Most flame sensors don’t sustain any damage. You should only observe a coating of carbon buildup or soot. However, you might also notice rust, fractures, or other evidence of material damage.
If you think your flame sensor sustained damage, you should look into a replacement as soon as possible. Flame sensors prevent your furnace from dangerous malfunctions. They also ensure your furnace will keep your family comfortable throughout cold weather.
#4 Carefully Clean the Sensor
If your sensor doesn’t show signs of damage, proceed to clean it. Use the steel wool or sandpaper to gently scrub the sensor free of buildup. Use cautious, gentle scrubbing motions to avoid damaging or scratching your sensor.
Then, carefully wipe the sensor with a paper towel or an Emery cloth until the metal looks free from any remaining detritus. Finally, inspect the connecting wires for rust or corrosion. Wipe the wires down as well to ensure a secure connection.
#5 Replace the Furnace Flame Sensor
Using the screwdriver, secure the furnace flame sensor in its original location. If you disconnected it from the cable, reconnect it before mounting it again. Replace the access panel and power your furnace back on.
Flip the switches in the circuit breaker back into the “on” position. If you had to turn the gas off before, turn it back on so it can flow into your home. Your furnace may take a few minutes to begin functioning again.
This delay should cause you no concern. Your furnace goes through system checks to ensure everything works properly before ignition. If your furnace doesn’t begin supplying heat to your home, you may need to replace your flame sensor.
When to Replace a Damaged Furnace Flame Sensor
If you have a faulty flame sensor, shop to find one that matches your furnace’s requirements. Most flame sensors only last between five and ten years. While pricing depends on what your furnace system needs, most sensors don’t cost a lot of money.
After obtaining your new flame sensor, you’ll follow the same process as you did when you cleaned it. Instead of cleaning your old sensor, you’ll replace it with the new one in step four. Your furnace should work once you finish.
If it doesn’t, then it harbors a hidden problem that requires help from an HVAC technician.
Choose Leith Heating & Cooling for Any HVAC Need
Now that you know how to clean a furnace flame sensor, you understand your home HVAC system a little more. You should clean your sensor yearly. This also provides an opportunity for you to look for any developing issues.
If you notice anything odd, call us at (847) 860-7092 for furnace maintenance services. Our technicians at Leith Heating & Cooling will get your furnace up and running in no time.
