There are several different types of flame sensor - some will raise an alarm while others may activate a fire suppression system or deactivate a combustible fuel line. In fact, many techs will just change the sensor for a new one as part of their maintenance procedures. The sensor should slide out where you can carefully remove it. A: The sensor is a small device that is made of a stainless-steel rod and encased porcelain. Carbon buildup can also cause a faulty sensor. You may also notice a sensor filled with corrosion and soot. The same thing goes for a furnace. The flame sensor, it turns out, is a key part of a safe ignition sequence. The best way to prevent these types of malfunctions and breakdowns is maintenance and on-time repairs. Or it can simply wear out. As the gas is ignited, the flame sensor generates a … A: The flame sensor can be easy to clean if you follow the steps carefully. Another sign is soot that covers the tip of the sensor. If no flame is detected, the furnace flame sensor will shut off the furnace in order to avoid a potentially harmful gas leak into the home. One of those components is the flame sensor. If your flame sensor doesn’t show any discrepancies in resistance, you can replace the flame sensor back in its place. The flame sensor sends an electrical signal to a central controller. The way it works is simple. The flame sensor is an essential part of the furnace’s safety system. You can check this by referring to the manufacturer’s instructions. The sensor is usually located on left side but on some furnaces it may be on the right side. It begins as the igniter or spark ignites the gas to create the flame. How a flame sensor look like. If the D0-LED does not light up check the following: However, if you always keep your flame sensor clean, it could just be that the sensor has gone bad. You can complete the test by pressing the open end of the sensor to a 60-watt light bulb or a test lamp designed for flame sensors. So, it is very important that your sensor is working correctly and not damaged or misreading the electrical feedback from your furnace. How to clean flame sensor. This sensor is used in industrial boilers. Next, simply replace the flame sensor back in its place. However, over time, the constant heat/cool cycles cause the igniter to crack and fail. You will need a ¼-inch hex driver, light grit sandpaper, emery cloth and steel wool. As part of the furnace thermocouple, the flame sensor piece is what’s responsible for measuring heat coming from your lit pilot flame. Just remember to have the proper tools and equipment if you do decide to handle this project yourself. If this is the case, you will need to shut off the gas going to the furnace. Some furnaces will come with a gas valve that is not electronically controlled. Some sensors are straight; some have a 45-degree or 90-degree bend near the end. Another reason can be due to age and usage of the sensor. During ignition your furnace’s igniter will use a flame or a hot surface to ignite the gas that heats your air. A flame sensor detects the presence of fire or flames. There’s not much to this component – you’ll see a thin, rounded rod about the diameter of a coat hanger near your row of burners. This is being caused by a component failure in the flame sense circuit and prevents the furnace from being reset. This is where the flame sensor comes in. Flame Sensor: A Crucial Part of a Furnace, Furnace Transformer - What It Is and How Does It…, Furnace Thermocouple - The Ultimate Guide, Inducer Motor and Blower: Why Your Furnace Needs One. If you can send me a link to yours I can … As an Amazon Associate we earn from qualifying purchases. It will shut down the unit even if it is producing heat. Once you remove the flame sensor, just rub the rod with a light grit sandpaper. You can keep your sensor clean by maintaining it on a regular basis. Once you’ve double checked that all power or gas has been shut off on your furnace, you can remove the flame sensor. You can check this by performing a test on the flame sensor. Would recommend it for any flame sensor type issues you are having. This is a safety mechanism. It can detect infrared light with a wavelength ranging from 700nm to 1000nm.The far-infrared flame probe converts the light detected in the form of infrared light into current changes. Once you have the proper tools, you can start the cleaning process. Like many components and parts found throughout your HVAC system, flame sensors can malfunction on their own and are important to replace before they fail completely. It helps your furnace regulate the ignition sequence and prevent dangerous conditions. When your furnace is well-maintained and working properly, it doesn’t pose any safety risks to your home. However, over time, the constant heat/cool cycles cause the igniter to crack and fail. It detects and confirms whether or not there is a flame burning inside of the furnace. If your furnace uses an electronic controller, it’s got a flame sensor. Whether you want to repair, install or perform maintenance tasks on your furnace, you do need to know its components. They all work best the more you know about them though, so let us dive into the specifics of how a flame sensor works. Testing: To test the Flame Sensor and ensure that it is working correctly connect the VCC to a 5v power source and GND. If, on the other hand, a certain period of time elapses in which the flame sensor cannot detect a flame, it will automatically shut off the gas valve. A flame sensor module that consists of a flame sensor (IR receiver), resistor, capacitor, potentiometer, and comparator LM393 in an integrated circuit. If the control board does not read the correct level of electrical current, the furnace will cut off the fuel intake to prevent an explosion or fire. A gas dryer blows air through a burner assembly to heat the air. A flame sensor detects the presence of fire or flames. All gas dryers operate … If you feel safer, you can also shut the power off on the furnace itself. This should complete the process of cleaning the sensor. A: Well, the most common signs of a bad flame sensor can include gas burners lighting and then going out after a few seconds. Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line (such as a propane or a natural … By going over this topic, you are sure to understand its mechanics and overall purpose. The furnace’s computer uses the signal from the flame sensor to confirm a successful ignition and turn off the igniter. Now that you’ve disconnected the boots and leads, you have to set your multimeter to show resistance. The metal end of the flame sensor can rust over time. The porcelain insulates the sensor against grounding itself on the metal furnace frame. The word sensor can be defined as an electrical device that is supposed to sense a feature or activity. This sensor completely address the turn off and turn on issues I was having with my hayward heater. This is where the flame sensor comes in. What Does A Flame Sensor Do? A furnace flame sensor works to regulate the flow of gas coming into your furnace and automatically shuts down the unit if the gas burners do not light as to prevent gas build-up or worse, gas poisoning or catastrophic explosion. You should be getting a low resistance reading on your multimeter. The furnace comes with many components to analyze. All you need to do now is disconnect the leads, which can be done by pulling the wire boots. A flame sensor is an important safety element on your gas heating equipment. It may be necessary to pipe in clean outside air for combustion into the appliance enclosure, or use a direct vent appliance that uses outside air for combustion. The flame sensor is a metal rod with white or dingy yellow/brown porcelain surrounding the mounting end. We’ve established earlier that a flame sensor is a device used to detect fires in furnaces but it can be referred to as a piece of safety equipment as well, providing confirmation as to whether the furnace is … Heating continues when the sensor detects the flame and all is well with the furnace. The flame sensor produces a small amount of electricity during ignition, which interacts with the igniting flame or ignition surface to ensure the right amount of gas is lit. What Does … FLAME SENSOR VS. THERMOCOUPLE. Thermocouples are used on standing pilot furnaces that have pilot lights. The same is true with flame sensors. Whenever I do these types of tests on my furnace, I can usually find the flame sensor inside the rear or front access panel. It does this by generating a potential (voltage) at the flame sensing terminal, this terminal is connected to the sensor with a conductor. To learn more or to schedule a maintenance check if you suspect a problem with your furnace, contact our St. Louis heating & air conditioning specialists at Galmiche & Sons today! As with any mechanical part, you should always keep it clean for optimal performance. Flame sensing rods stick out into the flame and connect back to the furnace board. The flame sensor in your photo uses the electrode in the flame vs. the frame of the furnace (which includes the root of the flame) and is connected to the mounting lug on the flame sensor (that's why there is a ceramic insulator in there). It’s not much more than a thin, usually bent, metallic rod that sits in front of the flame stream inside the furnace. It is also important to note that the flame sensor is extremely sensitive and delicate. Q: What does a flame sensor do in a furnace? 3. The furnace will come with a control board that measures this reading once the ignition process starts. Home » Flame Sensor: A Crucial Part of a Furnace. And the flame sensor can develop surface corrosion, causing it to send an incorrect signal to the computer. However, if the furnace flame sensor does not detect the presence of a flame within 10 seconds of the gas valve opening, it will shut the furnace down. A: The short answer is it regulates the fuel or gas inside a furnace to prevent major malfunctions, such as an explosion. Turn off the gas feed going to the heater. In extremely hazardous environments, flame sensors work to minimise the risks associated with fire. A ground path is the other half. It does not feel heat, it instead passes a small electrical current thru the fire itself, so it has to be in the flame. Should I just clean the flame sensor or replace it? Submit your email address below to get our latest posts and tips delivered right to your inbox. Think of it as a chain reaction. A flame sensor detects heat coming from the burners. One such component is the flame sensor. The flame sensor is able to detect the heat caused by combustion. Although the word flame goes hand in hand with furnace, the word sensor may throw you off a bit. This one explains the electronics behind the flame rod control system. You may find many reasons why a flame sensor is not working. You may also find the white porcelain of the flame sensor cracked or broken. The rust builds up and prevents the flame sensor from producing the current that tells the control board that it detects the flame. A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection. At this point, I would like to give you another friendly reminder of turning the power off at your circuit breaker. This central controller operates the gas or fuel valves for releasing the combustible materials into the burning chamber of the furnace or boiler. During the ignition cycle, your gas furnace undergoes a process where either a hot surface ignitor or a spark actually ignites the gas. Make sure that you also look at the porcelain on the sensor. The flame sensor, then, is a safety measure. Gently clean and rub the metal rod with the sandpaper. Flame rods are found on nearly all induced draft burner systems and on many forced draft burners. As a safety precaution, you can replace and install a new flame sensor every two to three years. Burner surface to flame sensor is 4:1 ratio thus causing the AC current to change to DC current. Or it can simply wear out. For instance if you read the value one at a time, you could use your sensor to figure out which direction a flame is in (at a short distance, depending on the sensor). One key aspect of HVAC safety and maintenance is regular cleaning, with special attention to safety components like sensors and other diagnostics. Once the board sends a call to the gas valve to open, it monitors the current flow on the flame sensing rod. Even though it may not cause an explosion, your furnace may stop working altogether, which can be inconvenient. A small piece that communicates between your furnace’s ignition and control board, the flame sensor may appear unassuming but it is a crucial part of HVAC safety. A Flame Sensor is a device that can be used to detect presence of a fire source or any other bright light sources. If you are heading into the winter months, I would recommend checking your furnace as soon as possible. When this happens, there's a tiny shockwave that occurs around that explosion (along with the normal detonation from the spark plug), which greatly increases the pressure in the cylinder. The following image shows an Infrared type Flame Sensor. Troubleshooting: . Dirty or Defective Flame Sensor. A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection.Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line (such as a propane or a natural gas line), and activating a fire suppression system. It replaced the old sensor perfectly and was easy to install. One of the main reasons your furnace may stop working is because of a faulty flame sensor. Took all but 10 minutes to install. […] In a nutshell, the flame rectification system is an electrical process that causes a low level DC current to be conducted from the flame rod through the flame, and back to ground. If you’re like me, you want to know everything about a topic you’re working on or just researching. The price ranges can be anywhere from $350 to as much as $500. A furnace flame sensor is a specialized safety component that is located inside of the burner assembly of a furnace. Flame sensor working principle A Flame sensor works to regulate the flow of gas entering your furnace and automatically shutting the gas valve down if the furnace does not light up. The flame sensor, it turns out, is a key part of a safe ignition sequence. A: Now we’re getting to the good stuff. When your furnace starts and quickly shuts down, it’s time to clean the flame sensor. The purpose of the flame sensor is to confirm to the system that whenever the gas valve is open, a … The flame sensor’s job is to create a current of electricity. Some of which are so small and out of the way that you rarely notice them doing their job. Energy Efficient Heating: 5 Simple Tips to Help You Heat Your Home More Efficiently. The flame sensor is an essential part of the furnace’s safety system. If a wire is attached to the sensor, you may have to detach it to give yourself more room. In this case, the sensory feature of the furnace is to measure and sense the flame or spark from your pilot flame. What does a flame sensor do? The black object at the front of the module is this Photo Transistor. This current has to be on the proper level to function. As the gas is ignited, the flame sensor generates a current of electricity. How to Check the Flame Sensor. The flame detection response can depend on its fitting. So why is there a flame sensor in your furnace and how does it play such a crucial role in furnace safety? The sensor is mounted to the outside of the burner assembly. The furnace’s computer uses the signal from the flame sensor to confirm a successful ignition and turn off the igniter. Then, it interacts with the furnace’s control board to shut down the unit if necessary and prevent an explosion. If the furnace does light but shuts down immediately, this would indicate a flame sensor issue. It may seem like there are endless HVAC components to clean, replace, and worry about. It is commonly bent at about a 45-degree angle (this is so it can be in position to accurately sense the heat from the pilot light telling the system the furnace is ready fire up). There are several ways to implement a Flame Sensor but the module used in this project is an Infrared Radiation Sensitive Sensor. This video demonstrates how to test a flame sensor on a gas dryer. If it is cracked, you could be dealing with a broken flame sensor. In this case, you can try to replace the flame sensor yourself. On most modern units, this shutdown can happen up to three times before the system goes into a lockout and sits for an hour before it … This can include the cost of travel and the diagnostics charge. It includes an alarm system, a natural gas line, propane & a fire suppression system. The word sensor can be defined as an electrical device that is supposed to sense a feature or activity. The flame sensor is able to detect the heat caused by combustion. When it does, it sends the signal to stop powering the hot surface igniter. Make sure that you also have extra paper towels on hand. This would include the flame sensor. That electricity is sent to the gas valve and allows the gas to … If the flame sensor fails, the ignitor may not go off and the gas flow will not start. When your flame sensor malfunctions, it is ideal to fix it as soon as possible. The sensor can be easily found and removed with the ¼-inch hex screwdriver. First find the flame sensor. How much should it cost to replace? This will include the proper tools. The purpose behind such working principle is to prevent built-up gas or catastrophic explosions. Galmiche & Sons Heating & Cooling - 2280 Chaffee Drive, St. Louis, MO 63146 - Phone: 314-993-1110, Office Hours Monday - Friday: 7:00 am - 4:30 pm Saturday: 7:00 am - 11:00 am, HVAC Services by City | Commercial HVAC by City | Furnace Repair by City | Air Conditioner Repair by City. I’ve had my heater quit on me in the middle of winter, and it was not fun. The YG1006 Photo Transistor looks like a black LED but it is a three te… Should combustion be disrupted for any reason the sensor loses its signal and shuts the gas valve off. Is able to what does a flame sensor do the heat caused by combustion this by touching the probes on the flame or a surface... Fuel valves for releasing the combustible materials into the burning chamber of the dryer sensor. Bright light sources cleaning, with special attention to safety components like and... 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Releasing the combustible materials into the burning chamber of the furnace steel wool over the sensor in furnace... The sandpaper could affect its performance is cracked, you may also notice a sensor filled with corrosion and.! Are sure to understand its mechanics and overall purpose how does it work type dust! Have extra paper towels to wipe off any dust and debris it may be on the flame sensor back its...