Joinwin Electronics HK Limited518031About Join WinJoinwin Electronics HK Limited FLAT/RM 29, 22/F, YAN’S TOWER, 25-27 WONG CHUK HANG ROAD,ABERDEEN HONGKONG Shenzhen ZhongYiYingTong Technology Limited Room 1610, Block A, Overseas Decorative Building, Zhenhua Road,Huaqiang North Street, Shenzhen, 518031Join-Win will be your one-stop purchasing assistant. Join together, achieve win-win!Joinwin Electronics HK Limited518031About Join WinJoinwin Electronics HK Limited FLAT/RM 29, 22/F, YAN’S TOWER, 25-27 WONG CHUK HANG ROAD,ABERDEEN HONGKONG Shenzhen ZhongYiYingTong Technology Limited Room 1610, Block A, Overseas Decorative Building, Zhenhua Road,Huaqiang North Street, Shenzhen, 518031Join-Win will be your one-stop purchasing assistant. Join together, achieve win-win!Joinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics HK LimitedJoinwin Electronics

Home
News
What is furnace flame sensor, furnace flame sensor working principle and maintenance cleaning

What is furnace flame sensor, furnace flame sensor working principle and maintenance cleaning

July 28 , 2023 0

Flame sensor is the robot is specially used to search for the fire source of the sensor, of course, the flame sensor can also be used to detect the brightness of the light, but this sensor is particularly sensitive to the flame. Flame sensor using infrared light on the flame is very sensitive to the characteristics of the use of special infrared receiver tube to detect the flame, and then the brightness of the flame into a high and low level changes in the level of the signal input to the central processor, the central processor according to the changes in the signal to make the corresponding programme processing.

What is a flame sensor and how does it work?

Flame sensors, as the name implies, are used to detect and respond to the presence of fire or flame.

Flame sensors typically sound an audible alarm, deactivate fuel lines (such as natural gas or propane lines), and activate different types of fire suppression systems.

Flame sensors are often used to check if a furnace is working properly. These sensors are also used in ignition systems to take accurate action or to notify the operator. Flame sensors or flame detectors are more accurate and faster than smoke or heat sensors.

What types of flame sensors are there?

Understanding the various types of flame sensors is critical to maintaining and troubleshooting your furnace system. The following list highlights the most common types of flame sensors found in gas and oil-fired heating systems:

UV/IR Flame Detectors: These versatile detectors use ultraviolet (UV) and infrared (IR) technology to detect flames, making them a popular choice for furnace systems.

Flame Sensor Rods: Also known as flame rectifier rods, these devices are commonly used in hot surface systems to provide real-time information about the presence and quality of flames.

Infrared Sensors: Ideal for gas and oil flames, infrared sensors detect the heat generated by the flame and help ensure the safe operation of the furnace system.

Bimetallic Temperature Sensors: These sensors utilise temperature changes to determine the presence or absence of a flame by measuring the difference in expansion rates between two connected metal strips.

Ionisation probes: Using the small electrical charge generated by ionised gases, ionisation probes reliably detect the presence of flames within the furnace system.

Thermocouples: By measuring the voltage generated when two dissimilar metals come into contact with heat, thermocouples can provide valuable data on the presence and intensity of flames within a furnace system.

Ultraviolet Sensor:

Ultraviolet (UV) sensors detect UV radiation emitted during ignition. UV flame sensors can detect fires and explosions within 3-4 milliseconds. However, it is desirable to include a time delay of approximately 2-3 seconds to minimise false alarms that may occur due to

radiation from other UV sources such as lightning, radiation, arc welding and sunlight. UV detectors typically work better at wavelengths shorter than 300 nm, reducing the effects of natural background radiation. Oily contaminants can easily blind the sun-blind UV

band.

Infrared Sensors:

Infrared (IR) or broadband infrared (over 1.1 μm) flame detectors sense and analyse the infrared spectral bands to look for certain predefined patterns emitted by hot gases. These patterns are sensed or detected through the use of a thermal imaging camera or

thermographic camera. Near-infrared flame sensors work with flame recognition technology to detect near-infrared radiation using CCDs or charge-coupled devices. Water vapour significantly affects infrared radiation sensors because water absorbs most of the

received infrared radiation. As a result, infrared sensors cannot provide accurate results in outdoor environments.

Visible Sensors:

Visible flame or radiation sensors are used to provide an output image of a radiation pattern that humans can understand. These types of sensors are often interfered with by smoke and fog. V Visible sensors are often used in conjunction with UV sensors or infrared

sensors to gather information, improve detection output and detect false alarms. Corona cameras are an example of a combination of UV and visible sensors. These sensors are particularly capable of detecting flames over long distances.

IR3 Flame Detector:

The IR3 Flame Detector compares the radiation maps between three different infrared spectral bands and the ratio between the bands. Typically, such sensors are programmed to detect one band of radiation belonging to the 4.4 micron range and two other bands of

radiation belonging to the range above and below the 4.4 micron spectrum. In this way, the detectors are able to distinguish between the actual flame and the non-flame radiation that affects the results. As a result, these detectors are able to provide better flame

detection results by ignoring background radiation.

In addition to the UV, IR, visible and IR3 flame detectors, several other detectors were found; such as 3 IR+UV flame detectors, IR/IR flame detectors, UV/IR flame detectors and thermal imaging cameras.

The Importance of Flame Sensors in Gas Heating Systems:

Flame sensors play a vital role in maintaining the safety and efficiency of gas heating systems. They are an important safeguard that prevents the flow of fuel without ignition and prevents dangerous gas leaks or explosions from occurring.

This critical component not only helps ensure your home's safety, but also helps ensure your furnace is operating at optimal levels for energy efficiency and reliable heating during the colder months.

A well-functioning flame sensor prevents unnecessary stress on your HVAC system and helps prolong its life by constantly monitoring combustion control.

Signs of a Faulty Flame Sensor:

A faulty flame sensor can cause a variety of problems with the heating system, including failure to ignite or short cycling, shutdown during operation, error codes on the furnace control, and abnormal flame patterns.

Failure to light:

One of the most common signs of a faulty flame sensor is when the cooker fails to light. When this happens, you may hear a clicking sound as the furnace tries to light, but it shuts off shortly after the attempt.

In other cases, the furnace may not even try to light at all. This happens because there is no active flame in the combustion chamber, and gas continues to flow into your home, posing a risk of carbon monoxide poisoning and gas leaks.

Regular cleaning and maintenance of your furnace's flame sensor is critical to preventing failure-to-ignite issues and ensuring your furnace runs smoothly throughout the winter.

Neglecting regular maintenance can lead to a build-up of dirt on the surface of the sensor, which may interfere with its signal transmission due to a lack of proper electrical conductivity between the sensor and the circuit board or other components of the heating system.

Short Rides:

Short cycling occurs when a furnace is repeatedly turned on and off for short periods of time, usually less than three minutes. This can be caused by a number of factors, but a common cause is a faulty flame sensor.

When the sensor fails to detect an active flame, it indicates to the control board to shut down the system as a safety measure. When the sensor detects another flame, the furnace will restart again, causing the furnace to turn on and off continuously. Other possible causes of short cycles include blower motor problems or clogged exhaust flue.

Downtime During Operation:

If your furnace shuts down repeatedly during operation, it may be due to a faulty flame sensor. The flame sensor is responsible for detecting the presence of a flame and communicating with the furnace's control board to maintain smooth operation.

Other signs of a malfunctioning flame sensor include short cycling and unusual patterns in flame colour or shape. I t's important to address these issues in a timely manner to avoid potential hazards, such as carbon monoxide leaks Ensure that your heating system runs efficiently and reduces energy costs.

Error Codes on the Furnace Controller:

Error codes on the furnace controller may indicate a problem with the flame sensor. For example, if you see a rapid amber flash, this means that the flame sensing current is below 1.5 microamps and the flame sensor needs to be inspected and cleaned with proper gas flow.

A red flash on the furnace control is also a sign that the flame sensor is faulty and needs to be replaced. These codes are critical to understanding problems with your heating system because they can help identify problems before they become major malfunctions.

If you notice any unusual error codes on your furnace controller, it is best to call a professional HVAC technician to diagnose and fix any problems in a timely manner.

Abnormal Flame Patterns:

An abnormal flame pattern in your furnace can be a sign of a faulty flame sensor. If the flames are yellow or have yellow and blue streaks, it could mean a problem with the furnace's heat exchanger or fuel supply.

These unusual flame patterns can cause problems with your heating system and even pose a safety hazard, such as a carbon monoxide leak. It's important to call an HVAC technician to check and fix any problems with the flame sensor or other components, and to promptly address any unusual furnace behaviour.

Maintenance and Cleaning of Flame Sensors:

To ensure proper functioning, it is important to clean and maintain your unit regularly Furnace Flame Sensors.

The importance of regular cleaning and maintenance:

Regular cleaning and maintenance of your hearth flame sensor is essential to ensure the efficient operation of your heating system. Over time, dirt, dust and debris can build up on the flame sensor, making it less efficient at detecting flames and igniting burners.

This build-up can lead to a number of problems, including ignition failure, short cycling or shutdown during operation, abnormal flame patterns, and error codes on the furnace controller.

To prevent these problems from occurring, it is important to include cleaning the flame sensor as part of regular furnace maintenance. A Simple Step-by-Step Guide to Cleaning the Flame Sensor Includes turning off the furnace power before touching the burner

assembly, where you can slide the thin metal rod (flame sensor) out of the burner assembly.

A Step-by-Step Guide to Cleaning the Flame Sensor:

Cleaning Your Furnace Flame Sensor is an Important Part of Regular Maintenance This helps prevent future failures. Proceed as follows:

Turn off power To the furnace: Before you begin cleaning the flame sensor, be sure to turn off power to the furnace at the breaker box.

Locate the Flame Sensor: Typically, the flame sensor is located near the burner assembly in the furnace. If you cannot locate the furnace, refer to your furnace manual or consult your HVAC technician.

Remove the Flame Sensor: Using a 5/16-inch or 6/12-inch hex head nut driver with a 1-4-inch extension, remove the two screws holding the flame sensor in place. Carefully slide the sensor out of the bracket.

Cleaning the Flame Sensor: Using an emery cloth or soft bristle brush, gently wipe both sides of the cleaning metal rod until it is free of dirt and debris that could prevent proper ignition. A piece of sandpaper may also be used for this procedure.

Clean Electrical Contacts: Clean all electrical contacts on both sides of the flame sensor using electrical contact cleaner or topical alcohol.

Reinstall and test: Slide the clean and dry flame sensor back into the bracket and secure it with two screws using a hex head nut driver and the previous extension (only torque it slightly less than last time). Restore power to the furnace at the breaker box and run it for

a few minutes to test its function.

Remember, cleaning the furnace's flame sensor should always be done safely and methodically, following the manufacturer's instructions or consulting technician if necessary!

Checking for correct alignment:

It is important to ensure that the flame sensor is properly aligned with the burner flame for it to function effectively. An unaligned sensor may cause an error code or cause the furnace to shut down during operation.

To check the alignment

First turn off the power to the furnace and remove the access panel.
Locate the thin metal rod, which is usually located on the outside of the burner assembly
Check its position relative to the active flame produced by the furnace.

If you find that the flame sensor is not correctly aligned, simply use a small hexagonal screwdriver to adjust its position until it is correctly aligned, but be careful not to short out any other wires on the control board while performing this operation! Once re-aligned, replace all previously removed covers and restore power to the heating system, then test again.

Frequently Asked Questions:

Q: What is a furnace flame sensor?
A: A furnace flame sensor is a safety device used in heating systems to detect the presence of a flame. It ensures that the gas valve opens and gas flows into the burner assembly only when a flame is detected.

Q: How does the flame sensor work?
A: The flame sensor works by sending an electrical signal to the furnace control board. When the flame sensor detects a flame, it keeps the gas valve open, allowing the furnace to continue heating your home. If the flame sensor does not detect a flame, it signals the furnace to close the gas valve, preventing gas from building up in your home.

Q: What are some signs that your furnace flame sensor needs cleaning?
A: If your furnace's gas burner lights but the flame doesn't last more than a few seconds, or if the furnace cycles on and off repeatedly, it may indicate that your furnace's flame sensor is dirty and needs to be cleaned.

Q: How do I clean the furnace flame sensor?
A: To clean the furnace flame sensor, turn off the furnace and wait for it to cool down. Remove the furnace access cover and locate the sensor. Carefully slide the sensor out of the holder and use an emery cloth or soft abrasive pad to remove any carbon or debris from the tip of the sensor. Slide the sensor back into place and secure it with the bracket. Turn the furnace back on to test the flame sensor.

Q: What equipment do I need to clean the furnace flame sensor?
A: To clean the furnace flame sensor, you will need soft abrasive pads or emery cloths, and a screwdriver or nut driver to remove the furnace access cover and sensor bracket.

Q: How often does the flame sensor need to be cleaned?
A: How often your furnace flame sensor needs to be cleaned may vary depending on your furnace model and other factors, but it's usually best to clean the flame sensor once a year to prevent malfunctions and keep your furnace running smoothly.

Q: Will a dirty flame sensor cause my furnace to stop working?
A: Yes, a dirty flame sensor can cause your furnace to stop working because it prevents the furnace from detecting the presence of a flame. If the furnace control board does not receive a signal from the flame sensor indicating the presence of a flame, it will shut off the gas valve to prevent gas build-up in your home.

Q: What should I do if my furnace flame sensor fails?
A: If your furnace flame sensor has failed, it will need to be replaced. Contact a qualified technician to diagnose the problem and replace the sensor if necessary.

Q: Can I test the furnace flame sensor myself?
A: Yes, you can test the furnace flame sensor yourself using a multimeter or ohmmeter. Disconnect the sensor and use a multimeter to check for continuity between the sensor terminals. If the sensor does not show continuity, it may be defective and will need to be replaced.

Q: Are all furnace flame sensors the same?
A: No. Furnace flame sensors may vary depending on the furnace model and manufacturer. Be sure to use the correct flame sensor for your specific furnace make and model to ensure proper operation.

Conclusion

In conclusion, proper care of the furnace flame sensor is vital to the efficient and safe operation of your heating system. By regularly cleaning and maintaining your flame sensor, you can save money on repairs, avoid hazards, and ensure your furnace runs smoothly throughout the winter months. It's important to note that a dirty or malfunctioning flame sensor can cause abnormal flame patterns, downtime during operation, or error codes on your furnace controller. That's why it's crucial to know the signs of a malfunctioning sensor and how to clean or replace them if necessary. Flame sensors play an important role in ensuring the safety of your heating system while reducing problems such as gas leaks or carbon build-up.