Learn the 5 most common electrical issues, including blower motor failure and short circuits.
It is one of the most frustrating scenarios for an Asheville homeowner: It’s a cold night, the heat kicks on, and suddenly—click. Everything goes silent. You walk to the electrical panel, flip the breaker back on, and twenty minutes later, it happens again.
Stop right there.
If your furnace is repeatedly tripping the circuit breaker, it is not a nuisance; it is a safety warning. The breaker is designed to cut power when the system is drawing too much electricity, preventing fires and catastrophic damage. While some causes are minor, others indicate a serious electrical fault.
Before you call for emergency heating repair, here are the 5 things you can check to troubleshoot the problem safely.
1. The Air Filter is Clogged
Believe it or not, a $10 air filter is the most common reason for a furnace to trip a breaker.
The Science: When your air filter is packed with dust, pet dander, and debris, your furnace has to work overtime to pull air through it. This resistance forces the blower motor to work harder than it was designed to. As the motor strains, it draws more amperage (electrical current) to compensate. Eventually, that amp draw exceeds the limit of your breaker, and click—the power cuts to save the motor from burning out.
The Fix: Check your filter immediately. If it’s dirty, replace it. Reset the breaker once. If the system runs smoothly afterward, you’ve solved the problem.
2. Your Air Vents are Blocked
Many homeowners close vents in unused rooms to “save money,” but this actually hurts your heating system.
The Science: Your furnace is designed to move a specific volume of air (measured in CFM). When you close too many supply vents or block return vents with furniture, pressure builds up inside the ductwork. Just like with a dirty filter, this back-pressure forces the blower motor to work harder, increasing the electrical draw until the breaker trips.
The Fix: Walk through your home and ensure all supply vents are open and that no rugs or couches are blocking your return air grilles.
3. The Blower Motor is Drawing Too Many Amps
If your airflow is good (clean filter, open vents) but the breaker keeps tripping, the issue might be deep inside the furnace cabinet.
The Science: Your furnace relies on a specific component called a Squirrel Cage fan to move air. Over time, this fan can become weighed down by heavy dust buildup, or the motor bearings can seize up due to age.
When a motor struggles to spin that heavy squirrel cage, it pulls massive amounts of electricity—often spiking well above the safety rating of your circuit breaker.
The Fix: This requires a professional repair. A technician will measure the “Amp Draw” of the motor. If it’s pulling more power than the manufacturer’s rating, the motor or the capacitor likely needs to be replaced.
4. You Have a “Short Circuit”
This is the most dangerous scenario on the list.
The Science: A short circuit happens when a hot wire (carrying current) touches a neutral wire or a grounded metal surface. This creates a path of least resistance, causing a massive, instantaneous surge of electricity that trips the breaker immediately. This can be caused by rodents chewing through wires, vibrations loosening connections, or insulation melting due to age.
The Symptoms: Unlike a motor strain (which might take minutes to trip the breaker), a short circuit usually trips the breaker instantly the moment the furnace tries to turn on.
The Fix: Do not reset the breaker. Repeatedly resetting a short circuit can cause an electrical fire or destroy your furnace’s control board. Call a professional immediately.
5. Shared Circuit Overload
Sometimes, the furnace isn’t the villain—it’s just the victim of a crowded circuit.
The Science: Building codes usually require a dedicated circuit for a furnace. However, in older homes or finished basements, you might unknowingly have other outlets sharing that same line. If you recently plugged in a space heater, a vacuum cleaner, or power tools on the same circuit while the furnace was running, the combined load will trip the breaker.
The Fix: Check what else lost power when the breaker tripped. If other lights or outlets went dead, unplug those devices and see if the furnace runs reliably on its own.
When to Call the Pros
If you have changed the filter and opened the vents, but the breaker continues to trip, you have an electrical issue that requires a certified HVAC technician. Continuing to force the breaker on can turn a repairable part into a ruined system—or a house fire.
Electrical issues are dangerous. Call Comfort Central.
Our team in Asheville and Brevard can safely diagnose the root cause, check your motor’s amp draw, and inspect your wiring to keep your home safe and warm.