When Should You Replace Your Furnace Flame Sensor?
One of the most common furnace problems homeowners experience is a dirty or failing flame sensor. If your furnace starts and then shuts off a few seconds later, a flame sensor may be the cause.
Many YouTube videos and online articles will tell you to clean your flame sensor. While cleaning may temporarily restore operation, the better question is:
Should you clean it, or should you replace it?
What Does a Flame Sensor Do?
A furnace flame sensor is a safety device that confirms the burners have successfully ignited.
When your furnace starts, the ignition system lights the burners. The flame sensor then sends a very small electrical signal back to the furnace control board. As long as the board detects that signal, it knows a flame is present and allows the gas valve to remain open.
If the board does not detect the proper flame signal, it closes the gas valve within a few seconds to prevent unburned gas from entering the furnace.
Without a properly working flame sensor, your furnace will not continue heating your home.
Why Do Flame Sensors Get Dirty?
Over time, flame sensors are exposed to:
- Carbon deposits
- Oxidation
- Dust
- Combustion by-products
These deposits build up on the metal rod and reduce the flame signal being sent back to the control board. Eventually, the signal becomes weak enough that the furnace enters safety lockout.
Should You Clean or Replace It?
Cleaning a flame sensor during routine furnace maintenance is perfectly acceptable as preventative maintenance.
However, if your furnace has already entered lockout because of a flame sensor issue, replacement is often the better long-term solution.
In our experience, once a flame sensor begins causing nuisance shutdowns, simply cleaning it may restore operation for a period of time, but it does not always prevent the problem from returning. Replacing the sensor eliminates a common wear item and can help improve long-term reliability.
Don't Wait Until You're Without Heat
Flame sensors are designed to be durable, and many continue working even after years of service. However, once they begin causing repeated ignition failures or nuisance lockouts, replacing them is usually inexpensive compared to the inconvenience of losing heat during the winter.
If your furnace:
- Lights then shuts off after a few seconds
- Tries to ignite multiple times
- Goes into ignition lockout
- Requires frequent flame sensor cleaning
it may be time to install a new flame sensor.
Flame Sensor Replacement in Ontario, Alberta & British Columbia
Whether you're located in Ontario, Alberta, or British Columbia, OEMHVACPartsCanada.ca supplies genuine OEM flame sensors for many of the industry's leading furnace manufacturers.
If you're an HVAC technician or a homeowner replacing your own flame sensor, we can help you find the correct replacement using your furnace model number.
Order Your OEM Flame Sensor Today
A failing flame sensor is one of the most common causes of furnace ignition problems, and fortunately one of the simplest repairs.