The furnace flame sensor ensures a safe and efficient heating process and detects a flame in the burner. Without a flame, unburned gas can pose serious dangers, such as carbon monoxide poisoning or even an explosion. To avoid them, the flame sensor acts as an important safety mechanism, automatically switching off the heating system when necessary.
Given its vital function, proper care of the flame sensor is imperative. Regular maintenance of this small but very important device is essential to keep your family and your valuables safe from potential damage.
Understanding the Role of a Furnace Flame Sensor
The purpose of the furnace flame sensor is simple – it is designed to detect the presence of a flame in the furnace. As soon as the sensor detects no flame, it causes the entire heating system to shut down. The flame detector ensures that the gas valve only opens when the furnace pilot light can ignite the gas. If the pilot light fails, the sensor sends a signal to the control board, which closes the gas valve to prevent danger.
To prevent the buildup of gases, take certain steps to keep your furnace safe. If it continues to switch off after starting, check the flame sensor. Even if the pilot light is in good working order, a dirty or faulty sensor can cause the gas valve to continually trip to close, shutting down your HVAC system.
Simply cleaning the flame sensor may restore the furnace to normal operation.
How to properly clean the furnace flame sensor?
Although many HVAC repair tasks require professional intervention, cleaning a furnace flame sensor is a task that you can perform easily on your own. Follow these simple steps:
- Switch off the appliance: Switch off the furnace quickly. Or, switch off the furnace at the switchboard to turn off the power. Please note that turning off the thermostat will not turn off the furnace. For homeowners with non-electrically operated gas valves, you must manually shut off the gas supply.
- Remove the Furnace Flame Sensor: Furnace flame sensors are typically easily accessible and simple to remove. Remove the access panel. Some panels slide off, while others may have screws or retaining knobs. A single ¼-inch hex head screw usually secures the sensor. Unscrew it to slide out the sensor.
- Clean the Flame Sensor: Clean the flame sensor after disconnecting it. Use fine-grit sandpaper or steel wool to gently wipe the flame sensor and remove any carbon deposits. Afterwards, wipe the rod with a paper towel and remove any grinding dust. Check for corrosion on the power lead and clean it.
- Connect the flame sensor back: Before reattaching the sensor, make sure to reconnect the power cable if you have disconnected it. Once the sensor is in place, replace the access panel to close the furnace. Finally, switch on the power to check if the unit works properly.
Note: If the furnace takes a few extra seconds to start, it’s normal. Sometimes, the fan might run briefly as the unit undergoes checks. If the issue persists, the flame sensor may be defective and require replacement.
If you want to keep your furnace and HVAC system in top condition, it’s best to rely on furnace experts. At Superior HVAC Service, we have certified technicians who are dedicated to providing exceptional products, warranties, and personalized customer service.
