The reset button is one of the furnace thermostat and controls that works as a safety feature, designed to quickly shut the furnace off to prevent overheating. If the button is tripped frequently, this could indicate a problem with the furnace. In today’s post, local heating and air conditioning company The Ice-Man shares an overview of what causes the furnace reset button to trip and how this issue can be fixed.
How It Works
A typical furnace is equipped with a cadmium sulfide cell, or cad cell, on the primary control system. It functions as a light sensor that informs the system when a flame is lit, much like how outdoor lights automatically turn on at sunset. Under normal operation, the reset button will be tripped if the cad cell stops sensing light from an open flame. The gas furnace will then have to be reset once the underlying issue is addressed.
Common Causes of a Tripped Reset Button
The furnace reset button may be tripped in one or more of the following conditions:
Loss of fuel — The furnace won’t generate a flame without gas or oil to burn. When you call for a refill, let your heating technician know that the tank is empty, as it will need to be primed first.
Closed or blocked gas valves — As with a lack of fuel, closed or blocked gas valves can also prevent the furnace from burning a flame.
Clogged air filter — The air filter in your HVAC system helps maintain indoor air quality and usually needs to be replaced every three months. A clogged air filter can increase the strain on your heating system and cause overheating, both of which can trip the reset button.
Dirty flame sensor — The flame sensor rod can get coated with dirt and other particles over time. Keeping the flame sensor rod clean can help prevent the tripping of the reset button.
What to Do If the Reset Button Keeps Tripping
The process for resetting your furnace will depend on what kind you have; however, it’s designed to be done without the aid of a professional. Your furnace user guide should outline the steps. You can also ask your HVAC technician to guide you through the process. If the reset button keeps tripping even after you’ve addressed the possible causes described above, seek the help of your HVAC technician.