Possible Causes of a Flame Sensor Malfunction The most common is that it is dirty. Because burning fuel of any kind produces trace amounts of moisture, over prolonged exposure to these conditions, metal will rust. Since your sensor is made of metal, rust can build up, preventing proper sensing of the flame.There are two possible reasons a flame sensor will not relay the proper information to the control board. The most common is that it is dirty. Because burning fuel of any kind produces trace amounts of moisture, over prolonged exposure to these conditions, metal will rust.
What makes a flame sensor go bad?
What are causes of a dirty flame sensor? As with any piece of equipment a simple reason could be that dirty flame sensor just goes bad. However a more common reason is that it is just dirty. It is a sensitive sensor so any type of dust or carbon buildup could cause it to malfunction.
What happens if a flame sensor fails?
Without a flame sensor, your furnace will keep emitting gas even when there's nothing to ignite it, resulting in hazardous gas buildup. If your flame sensor is dirty or faulty, it will automatically shut down the heating unit if it doesn't detect a flame.
How will you know that the flame sensor is faulty?
Signs of a bad flame sensor Furnace burners turn on but go out after a few seconds. Soot and other debris is covering the end of the sensor (cleaning the flame sensor may fix this issue rather than a flame sensor replacement) Tip of flame sensor is black. Porcelain/sensor casing is cracked.
How long should a flame sensor last?
What happens if a flame sensor fails?
Without a flame sensor, your furnace will keep emitting gas even when there's nothing to ignite it, resulting in hazardous gas buildup. If your flame sensor is dirty or faulty, it will automatically shut down the heating unit if it doesn't detect a flame.
Can you bypass a flame sensor on a furnace?
Yes. You can bypass the flame sensor. However, if you do so, you can't manually light your furnace, and you've got to have proper bypassing safety measures in place. But it's advisable not to bypass 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.
Should I clean or replace flame sensor?
Because your furnace's safety is of the utmost importance, it is always better to be safe than sorry and replace the flame sensor if it is malfunctioning. Even if the flame sensor is in proper working order, it is advised that you replace it every two or three years as a preventative measure.
How much does a flame sensor cost?
How often should you clean your furnace flame sensor?
What is the difference between a flame sensor and a thermocouple?
Thermocouples are used on standing pilot furnaces that have pilot lights. The thermocouple sits near the pilot light and gauges whether it's working properly, while the flame sensor detects that the burners are lit once they start to emit gas and the igniters light them up.
Can a new flame sensor go bad?
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.
Can hear your furnace click on but it does not fire up?
You Have a Faulty Ignition Sensor (Pilot Light) The pilot light or ignition sensor is usually the most common issue when your furnace will not ignite. This is typically the problem if you can hear your furnace click on but it does not fire up.
Should I clean or replace flame sensor?
Because your furnace's safety is of the utmost importance, it is always better to be safe than sorry and replace the flame sensor if it is malfunctioning. Even if the flame sensor is in proper working order, it is advised that you replace it every two or three years as a preventative measure.
Can a new flame sensor go bad?
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.
Why does my furnace flame keep going out?
If your furnace keeps shutting off, it could be due to low airflow. There are several indirect issues that cause low airflow. Dirty Air Filters. If you don't change your air filters often enough, the filters will become dirty and clogged, which means the heat exchanger retains heat and eventually causes it to overheat.
What makes a flame sensor go bad?
What are causes of a dirty flame sensor? As with any piece of equipment a simple reason could be that dirty flame sensor just goes bad. However a more common reason is that it is just dirty. It is a sensitive sensor so any type of dust or carbon buildup could cause it to malfunction.
What happens if a flame sensor fails?
Without a flame sensor, your furnace will keep emitting gas even when there's nothing to ignite it, resulting in hazardous gas buildup. If your flame sensor is dirty or faulty, it will automatically shut down the heating unit if it doesn't detect a flame.
How long should a flame sensor last?
How does a furnace work without a flame sensor?
It's a thin, metal rod that monitors the pilot flame. If the pilot flame goes out, the flame sensor will turn the unit off to prevent natural gas from leaking into the home. 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.
Why does my furnace flame keep going out?
If your furnace keeps shutting off, it could be due to low airflow. There are several indirect issues that cause low airflow. Dirty Air Filters. If you don't change your air filters often enough, the filters will become dirty and clogged, which means the heat exchanger retains heat and eventually causes it to overheat.
Are all furnace flame sensors the same?
– This symptom is often caused by a dirty flame sensor that can be easily cleaned. 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).
Can you use sandpaper to clean flame sensor?
Clean the Sensor. Once you have removed the sensor, gently rub the metal rod (only) with soft steel wool or soft scotch brie type pad NEVER USE SANDPAPER as it will damage the flame rod.
How does a flame sensor work?
A furnace flame sensor works by detecting the presence of a flame within the furnace. The sensor is a short length of thin metallic rod that creates a small current of electricity in order to confirm there is fire burning within the furnace.
How much is a dirty flame sensor?
Similarly, flame sensors often become too dirty and malfunction, but these sensors can be fixed with a thorough cleaning. However, if it's too far gone and you must replace the flame sensor, it will cost you anywhere from $80 – $250.
What are the most common problems with flame sensors?
Rust and corrosion are other very common problems for flame sensors and they too are caused by infrequent cleaning and maintenance. At the end of the day, the flame sensor is the front part of a low power electric circuit so it can suffer from the same problems all electric circuits can suffer from when it gets corroded.
How to fix the flame sensor not working on my furnace?
To fix this problem of the flame sensor not allowing the furnace to light we must clean the flame sensor. In some furnaces, this is easily done while with other gas furnaces the flame sensor is difficult to remove for cleaning. Before searching for the flame sensor for removal and cleaning we recommend you turn off the power to the furnace.
What is a flame sensor on a gas furnace?
The flame sensor within a furnace was created to ensure that the gas valve is opening only while the flames are burning. Otherwise, toxic gas could build up and result in a leak or fire. Flame sensors can be found in all modern gas furnaces and other gas-powered heating systems.
Why does my fire alarm go off so often?
Because your sensor spends so much time immersed in flame, it has a tendency to collect carbon deposits, dust and other particulates which can burn onto the sensor. These are very sensitive wires which have to detect fire in a very short window of time.
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