How often does a flame sensor go bad?

Note: According to, the expected lifespan of a flame sensor is about 5 years. Most furnaces last anywhere from 10 to 20 years. That means that you will have to replace a flame sensor 1x, 2x, or even 3x during a furnace’s lifespan.

How often should a flame sensor be replaced? Flame sensor lifespan If you’ve just replaced the sensor or had a new furnace installed, you can expect the flame sensor to last for about five years. The average lifespan of a furnace is 15 to 30 years, so you can anticipate a flame sensor replacement once or twice over the course of your homeownership.

Do flame sensors fail? 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.

Do flame sensors wear out? Do flame sensors wear out? Flame sensors wear over time. However, often the problem is a dirty sensor, rather than a broken one. Since these sensors are designed to have a low tolerance for reading variations, they might misread from the slightest carbon coating.

Why does my flame sensor keep going bad? What Causes a Flame Sensor to Get Dirty? It’s possible for a flame sensor to go bad, but more often than not, it is not broken, just dirty from carbon buildup. Because a flame sensor has a very low tolerance for variations in the reading it takes, the slightest coating of carbon can cause it to misread and shut down.

How often does a flame sensor go bad? – Related Asked Question

How do I know if my furnace flame sensor is bad?

First, check for your gas burners to light up and then go out after a few seconds. This is the most common sign of a sensor issue. Second, if you can actual see soot covering the tip of the sensor, it’s time for a cleaning. If you look at the tip and it’s black, it’s time for service.

How much does it cost to replace a flame sensor?

Flame Sensor

It stops your furnace from letting off large amounts of natural gas if it’s not working properly. If the sensor is bad, it won’t be able to sense heat and will turn the furnace off. The average cost to repair or replace a flame sensor is between $75–$200.

Can a furnace run without a flame sensor?

Without the flame sensor, if the pilot light goes out but the gas valve remains open, the gas will not burn and will seep out of the furnace. This is a dangerous situation that can result in gas poisoning or even an explosion.

How do you trick a flame sensor?

Luckily, making such a check is very easy:

  1. Take a multimeter with microamps (µA) measuring system.
  2. Keep the furnace system turned on.
  3. Connect it to the wire that is leading to the gas valve.
  4. Connect the other side of the multimeter to the sensor terminal.
  5. Take the lead away from the flame sensor.

Why do furnace flame sensors get dirty?

The flame sensor can become corroded due to carbon buildup from the flame. This can cause the sensor to fail. If the burner light goes out within seconds of switching on the unit, this is a telltale sign of a dirty sensor. If you see soot clearly covering the sensor, then it’s time for a cleaning.

How often should you clean the flame sensor in a furnace?

We usually advise that you schedule furnace maintenance every 1-2 years (ideally once a year) and duct cleaning at intervals of 3 to 5 years for a smooth-running system and excellent indoor air quality. That’s the minimum.

Can you clean the flame sensor?

We usually advise that you schedule furnace maintenance every 1-2 years (ideally once a year) and duct cleaning at intervals of 3 to 5 years for a smooth-running system and excellent indoor air quality. That’s the minimum.

How do I clean my furnace flame sensor?

We usually advise that you schedule furnace maintenance every 1-2 years (ideally once a year) and duct cleaning at intervals of 3 to 5 years for a smooth-running system and excellent indoor air quality. That’s the minimum.

How long does a furnace ignitor last?

Don’t worry—an ignitor that goes bad is common for most furnaces. Fortunately, you can replace the ignitor without replacing the full furnace. Most ignitors last about seven years. Keep reading to learn how you can tell if your furnace problem is a faulty ignitor.

Can a furnace flame sensor work intermittently?

The flame sensor is a safety component that detects whether or not there is a flame in the combustion chamber. If this sensor is dirty, the dirt can cause the sensor to operate intermittently. When this happens, your furnace will most likely light, but because the sensor can’t properly detect if a flame is present.

What does a flame sensor do on a gas furnace?

A flame sensor is a crucial safety component on your gas heating system. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor will actually ignite the gas. As the gas is ignited, the flame sensor creates a current of electricity.

Why is my gas 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.

Are flame sensors universal?

Universal flame sensors: You might not need an exact replacement part. Universal sensors are available too. They are available at Home Depot, Menards or other building supply store.

Can a furnace last 40 years?

Although some furnaces can last more than 40 years (extremely rare), the average life of a furnace is around 15 to 30 years. As long as you have scheduled annual furnace maintenance, it should easily last over 15 years. Just like your car, your older furnace may need some basic repairs.

How do I bypass flame sensor temporarily?

The process is rather simple:

  1. Shut off power and gas to the furnace.
  2. Remove the sensor.
  3. Clean away soot and corrosion with a clean emery cloth.
  4. Reinstall the flame sensor.
  5. Restart the furnace.

Are all flame sensors the same?

Not all furnaces have a flame sensor, but if your furnace has one, it will be mounted close to the burner with the metal rod positioned in the flame. Flame sensors vary in size (2 to 4 inches) and shape (see examples below).

What is a good flame sensor reading?

When the flame lights, you should read between 0.5 and 10 microamps (μA), depending on the furnace. Readings between 2 and 6 are common.

Why does my furnace turn off after a few minutes?

Dirty or faulty flame sensor

If your furnace turns off after a few minutes, there is a good chance it is caused by a faulty or dirty flame sensor. This vital component is designed to keep an eye on the gas burner. When it cannot sense that burner, the furnace runs then shuts off and starts again.

What causes furnace ignitor failure?

Take a Look at the Air Filter

As mentioned above, sometimes the cause of a furnace ignitor failing to ignite is due to a safety issue, such as a clogged air filter, for instance. Air filters should be changed on a regular basis, to prevent these kinds of problems. However, a lot of furnace owners fail to do this.

What causes a furnace ignitor to crack?

Electrical Issues

A power surge may negatively impact the ignitor and cause it to short-circuit. Most heaters may handle a range between 110 and 125 volts of electricity supply. Anything above that may cause the ignitor to fail.

How much is an igniter for a furnace?

Igniter Cost: The igniter costs no more than $30 to $50. Check with your furnace manufacture for the model number of your furnace so you can find the right igniter for your unit. Furnaces can last for several years, and hence it is not hard to find the right replacement part.

What is flame sensor made of?

A typical flame sensor is made of not more than a stainless steel flame rectifier rod that’s partially encased in porcelain.

What should furnace flame look like?

Your natural gas furnace’s burner flames should be almost totally blue. The sign of a good natural gas furnace, according to heating service professionals, is a roaring blue flame with a light blue triangle in the center. A sliver of yellow may also be present.