furnace breaker tripsFurnace Breaker Trips - Furnace breakers most often occur for a few reasons:

  • a bad circuit breaker
  • a bad furnace fan motor or component
  • poor airflow through the furnace

Let’s explore these reasons in detail and find out what you can do to fix a furnace breaker trip. Or perhaps you need to call for service to have the furnace breaker trip repaired? Whether you need to call for service or not there are some simple remedies you can do to check the system and possibly fix it yourself. We begin the basics first and move to the more complicated things.

Furnace Breaker Trips

Poor Airflow through the Furnace

This can be the result of a dirty air filter. The furnace blower motor has to work harder to move air when you have a dirty air filter. Therefore, always check your air filters to ensure they are clean and not loaded up with dust and debris. Other problems that can cause poor airflow through your furnace are:

  • breaker tripping furnace air filterCollapsed ductwork - in this case, you have a question. Has anyone done any work where the ductwork is located? Maybe the cable installer? Pest control? These things have happened before and they can result in poor airflow and lead to other problems like a furnace breaker tripping.
  • If there was no filter in the system it is possible the evaporator coil could be loaded up with dirt and debris. Everything the filter should have stopped ended up in the air conditioner evaporator coil.
  • Insulation inside the cabinet or the ductwork came loose and it blocks airflow.

Amperage and Circuit Breakers | Furnace Breaker Trips

All of these things can create poor airflow and that results in the fan motor working harder. When the fan motor works harder it pulls more amperage. Circuit breakers will trip when they reach a certain temperature based on the rating of the breaker. When a fan motor pulls more amperage through the circuit it creates more heat. That extra heat can cause the breaker to trip. The fix starts with checking the air filter and then checking everything else if you think airflow is the problem.

Bad Circuit Breaker

A bad circuit breaker can be causing the furnace breaker to be tripping. Unless you know what you are doing this will require the services of an electrician or HVAC technician. Breakers do go bad from time to time and cause nuisance trips. The fix is to replace the breakers.

Breakers can also go bad because they have a loose connection in the panel. A loose electrical connection causes extra heat from electrical arcing. The extra heat melts things and the problem gets worse. Call for help if you don’t know what you are doing. This will require you to open the breaker panel where there is high voltage.

Bad Furnace Blower Motor or Component

Sometimes the furnace blower motor or a motor component can cause the problem of circuit breaker tripping. The component here would be either a bad capacitor or a loose connection to the motor from the relay or circuit board. This can easily be rectified by check the electrical connections or testing the capacitor. This should be done by only a technician who has been trained to do it because it deals with high voltage. Motor windings or bearings could also be going bad causing the motor to pull extra amperage. In either case, a professional should be consulted for the repair.  They will have the knowledge, tools, and skill to make the repair.

Conclusion | Furnace Breaker Trips

Some of these things can be checked by you but other things need to be checked by an HVAC professional. We have another basic list you can check located here.

High Performance HVAC Heating & cooling

Furnace Breaker Trips

Reader FAQ for Furnace Tripping the Circuit Breaker


Why is my breaker tripping repeatedly?

Typically this problem occurs because of an overloaded circuit or a breaker that is bad. It is possible you have a short circuit and ground fault protection issue. If it is a newly installed furnace, call the HVAC contractor that installed the new furnace.

What size of breaker should my furnace use?

Furnace breaker size depends on the ampacity of the furnace. This varies from furnace type to furnace type. An electric furnace will use a larger size (rated in amps) breaker than a gas furnace. The maximum amp values for your furnace should be noted on a nameplate on the furnace. If in doubt, always consult a professional. Using the incorrect sizes for electrical equipment can result in a dangerous fire condition.

My furnace breaker tripped and won't reset?

It is possible you have a short circuit or ground fault protection issue. See FAQ #1 for more info.