How Long Do Flame Sensors Last?

HVAC topics can be tricky. Not everyone has the knowledge that comes along with knowing what heating and air conditioning entails.

Most single-family homes have an entire system that runs through their home that allows heat or cold air to be delivered to each room of the house.

Now, since we’re talking flame sensors (also knowns as flame rods), we’ll be talking about the heating system.

The flame sensor is the piece of equipment that detects hot air as it travels and the temperature at which it’s being delivered.

The best question may not be “how long do flame sensors last?” As opposed to, “how do I know if my flame sensor is bad?” The main reason being that a flame sensor can last for a number of years as long as it’s properly cared for. This includes cleaning the sensor because elements can cause buildup that will make it seem as if the sensor has gone bad.

I would estimate that there are a fair number of flame sensors that ended up getting replaced when all they needed was a good cleaning.

When you’re dealing with a heating system, there is carbon involved. And what we know about carbon in a heating system is that there is a fair amount of it.

Capture Credit: Amre Supply

If a flame sensor isn’t cleaned of the inevitable carbon buildup, it will simply stop working.

If a homeowner isn’t privy to the fact that it may just need to be cleaned, they can end up replacing a sensor that hasn’t actually gone bad yet.

Flame Sensor Buildup 

Let’s take a look at some of the ways in which buildup can happen, as well as the ways proper care can lead to a flame sensor that is going to last.

It’s not always going to be carbon that gets into the HVAC system to potentially dirty the flame sensor.

Have a Question? Ask HVAC Technician

Click here to use the chatbox to speak with one of our technicians.
No in-home service calls. No appointments.

There are other elements throughout the home that can get into the system and cause a flame sensor to stop working properly.

There are some common culprits when it comes to buildup on your flame sensor:

  • Cat litter
  • Laundry detergent and fabric softener
  • Pool or spa chemicals
  • Permanent wave solutions
  • Fertilizers

Now, the causes are not going to be limited to just these items.

There are other elements that can get into the HVAC system and cause your flame sensor to stop working properly.

In fact, there is usually a clear coating that ends up on the flame sensory, so you may not be able to see the buildup.

Once you clean off the sensor properly, it should go back to functioning like it’s supposed to.

Unless the flame sensor is physically damaged or broken, you typically won’t have to replace it.

They last a fairly long time, so most issues involved in the part not working right usually boil down to a fixable error.

Nine times out of ten, once you properly treat the flame sensor and clean it the right way, it will go back to working properly so you can keep getting heat throughout the house.

Properly Cleaning your Flame Sensor

If you happen to be in a situation where you think the flame sensor does need to be cleaned, there is a proper way to do so.

Ironically, if you clean the part incorrectly or with the wrong tool, you may end up needing to replace the sensor in the end.

So, be sure to purchase the right equipment before taking the part out to clean it off.

Also, be sure to inspect the sensor once you have it out and cleaned. If it is broken in any way, especially the porcelain, you may end up needing a new one.

Also, check for corrosion; if any part of it is corroding, it may be no good too. 

In order to properly clean your flame sensor, you will need a stiff steel wire brush or steel wool.

Cleaning it with another abrasive like sandpaper, plumber’s roll, or any other type of abrasive tool may render your flame sensor useless.

What happens if you use another tool to clean it is that the sensor ends up with scratches.

Once scratched, the contaminants will fill in those scratches and cause the flame rod to stop working again quickly. Be certain to use the right tools!

Knowing how important cleaning flame sensors is becomes one of the quickest rules for HVAC technicians.

This is due to the fact that many calls they end up on become a situation of just needing to clean a flame rod.

They call these nuisance shutdowns or “no heat” situations. These are failures that are simple to rectify.

So simple, in fact, that a simple google search or reading an article like this one can give users a solution to the issue without having to pay someone for an easy fix.

When you do clean your flame sensor, be sure to shut the furnace off and shut off power to the furnace.

You can also use an emery cloth to clean the soot from the sensor. This buildup is what will end up causing the sensor to fail.

Whether using a cloth, brush, or steel wool, it’s as simple as that to clean off your sensor.

Once you’ve completed the cleaning, you can reinstall the part and fire the furnace back up to see if it is back to business as usual.

Replacing a Flame Sensor

And then there will be those situations every so often when a flame sensor will be broken and in need of a replacement.

By following some simple steps, you can switch out your old sensor for a new one and get your machine back up and running.

It’s not so much a tricky process to switch out the old one, it’s more of a situation of taking proper care, so the new sensor isn’t damaged in the process.

Flame sensors are not indestructible, and they are a small part of your furnace. Use proper care!

Take the following steps if you’re needing to replace your broken sensor with a new one:

  1. Unscrew the fasteners that hold your flame sensor in place
  2. Your sensor will have a wire that will need to be disconnected next
  3. Take the new sensor and insert it into the opening where you removed the old one
  4. Resecure the sensor by refastening the screw to the sensor
  5. Reconnect the same wire you removed from the old sensor

Pretty simple, right? Replacing a flame sensor isn’t rocket science, so you can save yourself some money by replacing the old part yourself.

There are plenty of quick, easy tutorials if you need to see the process in action. Most furnaces and machines with a flame sensor will have a similar setup.

The sensor will look similar from machine to machine, as well, so it should be simple to locate the part as well.

Always be sure to give the furnace some time to cool down if it’s been running hot before you go to work on it.

Once you shut off the power and gas, give it a little time before you give the furnace a tap to ensure it’s cooled down before touching the parts that you’re going to work on.

If you’re having issues with your flame sensor, either of these resolutions should be able to fix the problem! You’ll be back to having a comfortable, heated home in no time.

Leave a Comment