Flame Sensor Troubleshooting: Expert Guide
We discuss one of the most common reasons for a furnace unit to experience mechanical difficulties - damage to the flame sensor.
25/02/2022
Heating systems have become a standard fixture in most homes, especially in regions that experience freezing winters. Most households use furnaces to provide the much-needed warmth. The furnaces heat the space within a home through hot air circulation.
The furnace unit is an important component of household comfort. It is often overlooked until a mechanical problem brings to light the silent contribution that this appliance contributes to the quality of your personal life.
Among the most common reasons for a furnace unit to experience mechanical difficulties is damage to the flame sensor.
What is a flame sensor?
A flame sensor is a vital safety component of your gas heating system. During the ignition cycle, your gas furnace goes through a process where a spark or a hot surface ignitor will be used to ignite the gas; as the gas is ignited, the flame sensor creates a current of electricity.
This electricity is quantified in micro-amps which are detected and read by the control board in your furnace. The control board will stop giving fuel to the system if it does not read the required number of micro-amps; it does this as a safety measure to avoid an explosion.
Reasons why flame sensors go bad
The most common reasons why flame sensors go bad include:
Dirt and debris build-up on the flame sensor
The surrounding environment usually causes the build-up of dirt and debris on the flame sensor. Furnace units are generally stored in attics or basements, which are generally not the cleanest of spaces.
The surrounding dust and dirt can easily get sucked into your furnace, which may lead to the build of dust and dirt over time on the flame sensor.
Carbon build-up on flame rods
Carbon build-up on flame rods caused by an improper air to the gas mixture is another reason flame sensors begin to experience difficulties. This imbalance is usually a result of the gas ports not being adjusted properly or not being adjusted accordingly for your altitude.
Gas companies typically recommend a green sticker inspection to ensure that the gas to air ratio and other gas-related checks were performed correctly.
Old age
Flame sensors usually function at an optimal level for about five years. If you have had your furnace system for over five years and have not replaced any of the components, it would be recommended to inspect your flame sensor and possibly replace it.
When experiencing difficulties with your flame sensor, you can use a variety of troubleshooting approaches to determine whether or not your flame sensor needs to be replaced or cleaned.
Flame Sensor Troubleshooting Tips
Check your filters
Clogged or blocked air filters can significantly affect the performance of your furnace unit or HVAC unit. Dirty filters interfere with the flow of air in your furnace system, and they also indirectly cause short cycling issues, making it hard to keep your home warm.
Check your air filters and ensure that they are not the cause of the furnace not performing to the required standard and change them or clean them if necessary.
Check batteries in your Thermostat
Another furnace troubleshooting flame sensor tip is to check your thermostat’s batteries.
The primary purpose of batteries inside your Thermostat is to save any programmed information to be used in the event of short power outages so that your heating system continues uninterrupted. If the batteries had died, you could experience a furnace distributing heat levels that might have you suspecting your flame sensor or filters.
Does the gas ignite?
For gas furnace troubleshooting flame sensor, listen and check if your gas ignites. Go to your furnace sensor and start it up. If you can hear the gas igniting, it should be audible and sound like jet engines. Check if the gas is igniting by listening in.
Does the gas stay lit?
When the gas ignites, listen in for a bit longer to ensure that the gas stays lit. If it turns off shortly after coming on, your flame sensor is not detecting a flame.
Action points
If your air filters and batteries are in good working order, but your gas does not stay lighted or fails to ignite, it could be due to a problem with the flame sensor. If this is the case, then your following steps should be as follows:
Clean the flame sensor
This is another way of flame sensor troubleshooting. Cleaning the flame sensor can be done at home using various techniques and tools. The materials best suited to clean the flame sensor are abrasive materials that can gently clean over the flame sensor.
Test the flame sensor
If your flame sensor does not look impaired and you are unsure if it is still functioning. Then use a multimeter to test your flame sensor and see if it is still fit and proper.
Call an HVAC technician
Assume you've cleaned or replaced the flame sensor but are still having problems with your furnace unit. In that situation, it is possible that the problem is beyond the scope of basic flame sensor troubleshooting approaches. In this instance, it is essential to contact a certified HVAC specialist to thoroughly evaluate your equipment.
Conclusion
The flame sensor on your HVAC device is a
sensitive safety component that should be
treated with critical importance.
Always
ensure that your flame sensor is fully
functional by testing it regularly. Use the
above-recommended flame sensor troubleshooting
techniques when experiencing difficulties with
your HVAC device that might be flame
sensor-related.
If the problems relating to your HVAC seem to go beyond your level of expertise and troubleshooting ability, then always have an accredited and trusted HVAC expert to assist you further.
But if the problem is a dirty flame sensor, then clean it yourself or visit this page for more information.