All furnaces have a reset button. The purpose of the reset button is to rapidly shut down the equipment when necessary. Under normal circumstances, all you need to do is press the reset button and your furnace will resume functioning normally. If the button keeps tripping when you don’t need it to, it can pose an annoying problem. What’s more, if you keep pressing the reset button to get your system working again, you might be damaging your furnace. When a furnace regularly trips its reset button, it is usually because it is overheating and needs to be repaired. Furnace repairs should be left to experienced heating, ventilation, and air conditioning (HVAC) technicians but there are some steps that you may be able to handle.

Let’s take a look at the causes of a furnace reset button tripping and at some solutions for the problem.

About the Furnace Reset Button

The reset button on your furnace exists for your safety. Its function is to turn the heater down quickly when it gets too hot so that it doesn’t trip your circuit breakers. The furnace reset button is usually red or yellow and can usually be found in the HVAC system’s blower compartment but the exact location will differ depending on your model.

It is not normal for the furnace reset button to constantly trip, so the fact that it is doing so means that there is a malfunction in your system.

Possible Causes of Frequent Reset Switch Tripping

Multiple factors can cause a furnace reset button to trip, including:

Overheating

If your furnace is not getting adequate airflow, it can overheat. Issues that cause overheating include dirty filters and blocked or closed vents.

Gas Valves That Are Obstructed or Closed

If your gas valves are blocked or closed, they can cause issues with your reset switch. You need your gas valves open so that your heater can get the fuel it needs to operate.

Dirty Sensor

Your heater’s flame sensor needs to function to keep the heater on. Causes of malfunction include dirt and debris on the sensor.

Low Fuel

Oil and gas heaters may trip the reset switch if the fuel level is too low for them to operate.

Ways to Stop Your Heater’s Reset Switch Tripping
Before you take steps to prevent your heater from tripping its reset switch, take the following safety steps:

• If you have a gas furnace, turn off the gas
• Switch the furnace off
• Turn your furnace off at the breaker

Once you have covered the steps above, you can:

Check Your Air Filter

Because a dirty air filter is a common cause of the furnace reset switch problem, this is the best place to start. It’s also a very easy problem to solve. Just switch the old dirty out for a new clean one. Let the system cool down for about 30 minutes and then switch it on.

Reset the Furnace

Sometimes the solution is as simple as using the same component that is causing the problem: the reset button. You will need to press the button for about 30 seconds for it to work. The button resets the system so that it can resume functioning as it should. If this does not work, you may want to go in for a more drastic reset.

For a gas furnace, do the following to reset it:

• Check to make sure that the pilot light is off
• Lower the thermostat’s temperature to its minimum
• Flip the furnace breaker off
• Close the furnace’s main gas supply but leave the pilot supply on
• Light the pilot light with a match by holding it to the opening of the jet
• Flip the breaker back on and open the main gas supply
• Press the furnace reset switch for 30 seconds and then turn the temperature up on the thermostat

For an electric furnace, do the following:

• Turn off the power supply to the furnace at the breaker
• Find the reset switch and press
• Cover the compartment and turn the power back on

Check the Cover

Sometimes the cover for your heater has not been put back on properly. If you have recently changed your filter or done something else in the unit, the poorly seated cover could be causing your system to act erratically.

Check Your Fuel

If you have an oil or gas furnace and the fuel is low, you might encounter a reset button problem. If the fuel is low, you might be able to fix the reset button problem by topping it up. It is a good idea to create a reminder so that you don’t allow your oil furnace to get too low during the months when it is being most heavily used. You don’t want your furnace to ever go completely empty since you will need the services of a professional to get it started again without causing damage. If your tank is empty, inform your oil company so that they can get a technician to prime your system before the tank is refilled. If there is plenty of oil, the problem could be that your fuel line has an obstruction.

Open Vents

For your furnace to do its job, you need to give it good airflow, which it won’t get if you have lots of closed vents. To prevent overheating, never close more than 20 percent of the registers in your home.

Check Outdoor Vents

Outdoor vents can sometimes get blocked by snow or ice. If you have recently had a winter storm, check your outdoor vents to see if they are blocked.

Clean Your Flame Sensor

If your flame sensor rod is dirty, it could be causing your reset button to trip. Locate the flame sensor — it should be under your furnace’s access cover — and remove it. Clean your flame sensor rod off if it is coated with dirt and reinstall it if it appears to be in good shape. You should regularly check and clean your flame sensor to keep this from recurring. Do not reinstall a furnace sensor if it appears to be broken, replace it instead.

Open Your Gas Valves

Make sure your gas valves are open since they can sometimes get closed by accident. If they are closed, your heater won’t work as it should. Make sure that the furnace is off and cooled down fully when you check the gas valves.

Check Your Pilot Light

While you are checking on your gas valves, take a look at your pilot light to make sure that it is lit.

Inspect Your Thermostat

Sometimes problems like furnace reset buttons tripping frequently arise at the thermostat. The problem can be bad wiring. If the wiring is the problem, you will probably need the services of an HVAC professional to solve the problem. Another possible thermostat-related problem could be the batteries. Programmable thermostats depend on batteries for power and if they run low, problems like a constantly resetting furnace switch may occur.

Check Your Circuit Breakers or Fuses

If a circuit breaker has tripped or a fuse has blown, that might be causing the furnace switch issue. Check your main electrical panel to find out if there is a problem there.

Try to Detect the Smell of Gas

If none of the options above work or if you smell gas, you need to get in touch with the professionals. If you smell gas when inspecting your furnace, evacuate your home and contact the gas company.

Routine furnace maintenance can prevent problems like a reset button that trips constantly. Have your furnace inspected and maintained regularly to keep your home comfortable and lower your energy bills. For help with a reset button that keeps tripping, or if you need help with a furnace restart, contact us for assistance. Set up an appointment and our technicians will get to work on your problem.