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Why Does My Furnace Keep Blowing the Fuse?

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Not enough or too much heat can disrupt furnace functions. If your furnace or heat pump keeps blowing its fuse, it may be best to get to the bottom of things before they worsen.

Blown fuses may be simple to remedy. However, intermittent electrical issues may hinder consistent quality heating.

Below you will learn all about your heaters and their electrical demands.

Furnace Keeps Blowing Fuse?

Minor issues with your heating and cooling systems may domino to worse problems. Left for too long, it may impact critical components such as your blower motor.

Your heating system keeps blowing its fuse, but why? You should find a more permanent solution than just another temporary fix.

Replacing loose wiring and failing valves may just be what you need. However, there are plenty of other issues with internal wiring that may impact furnace fuses.

Pay attention to the signs; you may get better insight into what's ailing your furnace or heat pump.

Warning Signs of a Blown Fuse

Besides total system shutdown, there are other noticeable indications of blown fuses. Unusual noises, odors, and uneven temperatures may be the best indications of too much power circulation.

  • Loud noises
  • Burning electrical odors
  • Electrical short circuiting
  • Failing blower motor
  • Cold air
  • Reduced airflow
  • Leaking air ducts

The list above indicates the most common effects of blown fuses. Resolving the problem as soon as you notice them may help prevent worse or permanent damage from being inflicted on your HVAC system.

Knowing the most typical causes may prevent fuses from blowing in the first place.

Where to find the fuse

Your heating system has various fuses. The main fuse facilitates overall power distribution. You can find it within a control panel that is next to the blower or motor.

Turn systems off and disconnect everything from the power source if smoke is already coming out of the control box. Remember that a loose wire is a fire hazard and can cause explosions.

Smoke inhalation or exposure can trigger asthma, allergies, eye irritation, and skin rashes. It is also detrimental for any carbon emissions to make it into your ventilation systems. Keep your family safe by reporting any anomalies immediately.

Call the fire department and gas company immediately if you hear strange noises followed by bangs, dings, or sudden booms. A fuse on the fritz may have already caused significant internal problems that require professional services to remedy.

What Causes a Blown Fuse?

If your furnace fuse keeps blowing, there may be a loose wire or too much heat inside the control board. Various electrical currents run through your heating system, powering different components.

Your safety valve is a mechanical component in gas furnaces that requires power. It opens and closes according to internal regulations to prevent excess heat and gas flow.

Such sophisticated systems require routine upkeep. Your HVAC equipment has many moving parts; one may stall while another overcompensates. Inadequate and overcompensating components may lead to blowing a fuse.

Here are some of the most common reasons behind that botched fuse.

Overheating | Too Much Heat

Overheating is always bad, especially for anything with electrical components. Heat pumps are less likely to overheat without a furnace fire to generate heat.

A gas furnace is more likely to succumb to excess heat. Still, a heat pump may eventually burn due to the waste heat from components overcompensating.

Homeowners, especially with gas furnaces, must constantly be on the lookout. Regular HVAC inspections are a must even after the winter season.

  • Too much heat triggers¬†the high-limit switch,¬†consistently turning systems on and off. It may cause a power surge strong enough to blow a fuse.
  • Blower motor malfunction can stem from the unnecessary or¬†higher voltage¬†that is induced into motors. The furnace motor only needs enough power to generate heat, and too much may throw motors into overdrive.

Faulty Wiring | Blower Motor Malfunction

If a fuse keeps blowing, it's almost always thanks to faulty wiring and defective electrical components. Your faulty furnace circuit breaker may also impact your main breaker.

If it's linked to a separate ventilation system like a nearby humidifier or air conditioner, faulty wiring in your furnace may instigate a series of electrical issues.

Any loose wires touching the metal frame may impact voltage distribution if your furnace is attached to a metal frame. Improper voltages may hinder the draft inducer and safety valve, withholding ignition and supply intake.

  • A¬†malfunctioning thermostat wire¬†touches the wrong receptors. Loose wires are generally hazardous, but the thermostat wire regulates the heating system and poses greater risks to your furnace or heat pump.
  • A fuse blowing may be due to the natural vibrations, which may loosen internal wires. Factory defects may also cause a defective transformer. A¬†faulty transformer¬†can't facilitate the correct voltage into your furnace or heat pump.

WARNING: Don't touch the metal frame of your furnace if it's overheating or short-circuiting to avoid electrocution and burns.


Water leaks are some of the worst issues anyone may have with their heating system. Water leaks can get into different components, such as burners and supply lines, and even your furnace fuse may be at risk.

You can also thank a dirty air filter if your furnace fuse keeps blowing. An air conditioning system attached or a nearby humidifier may also release droplets and saturate your furnace filter.

It's best to keep your furnace away from any other HVAC system, especially during cold weather. All mechanical devices produce waste heat, conflicting with surrounding temperatures, creating condensation.

  • An air filter leak can hinder a properly working furnace. Pollutants getting into your furnace or heat pump leads to low airflow.¬†Sediments¬†put too much pressure on blowers to compensate, which may blow a fuse.
  • Water leaks sloshing around pipes and chambers can defuse burners. Water droplets may lead to¬†excessive condensation, causing clogs and backflow. It is especially hazardous for a gas-fueled furnace.

How to Prevent Your Furnace Fuse Blowing

Regardless of the type of furnace you have at home, it pays to observe regular maintenance and inspection. If your furnace keeps blowing its fuse, there's a potentially hazardous problem.

Remember that the fuse handles electrical distribution and impacts nearly all internal components. There are steps to prevent fuses from blowing or disintegrating. However, you should know what to do and avoid instead of acting on things impulsively.

WHAT NOT TO DO: Ensure you refrain from posing any of these risks to your furnace.

  1. Improperly installing your furnace and its attachments, such as undersized ductwork.
  2. Failing to keep up with routine furnace maintenance. 
  3. Neglecting pre-season tune-up services for your furnace.
  4. Integrating any incompatible attachments, such as overpowering air conditioners.
  5. Attaching any links with unsuitable voltage.
  6. Keeping water around your furnace, air vents, and ductwork.

WHAT YOU SHOULD DO: By observing these preventive measures, you can prevent your furnace from blowing a fuse.

  1. Schedule quarterly maintenance services, especially before the heating season.
  2. Always take the option for a tune-up when the furnace specialist offers them. 
  3. Report any unusual noises, smells, and other activities immediately. 
  4. Keep animals, children, and automated cleaning devices away from your furnace.
  5. Protect the furnace from external elements such as dirt, dust, and other debris with a tarpaulin cover during the off-season. 
  6. Keep it safe from the wall and other fixtures that don't need to be linked to the furnace.
  7. Shift the thermostat temperature carefully and intermittently. 
  8. Ensure all furnace installation is proper and accurately measured.

The to-do list above may help maintain your furnace. However, you may still have heating concerns even when you religiously observe these guidelines.

You deserve reliable heating that won't stall when you need it most. A properly maintained heating system also keeps you away from fire hazards and surging energy costs.

Keep an eye on your furnace fuse, noting its behavior under various circumstances. If your furnace fuse keeps blowing even after repairs, there may be an underlying critical issue.

Problems With Your Furnace or Heat Pump?

Some maintenance workers may need to pay more attention to certain components instead of solely focusing on others. However, inadequate repairs will keep costing you without a permanent solution to your blown fuse.

Schedule a thorough inspection with reliable furnace experts if your furnace problems won't go away. Schedule an inspection, evaluation, maintenance, and repairs before winter rolls around!

You may spend a little more on prominent HVAC specialists, but rest assured; you will get to the bottom of things before you or your furnace blows a fuse!

Routine HVAC Maintenance and Repair

Faulty parts causing strange noises and uneven temperatures? Sunset Heating & Cooling's heating services can help with that!

We do everything from furnace repair, heat pump installation, and other electrical services. The next time your furnace or heat pump blows a fuse, call Sunset Heating & Cooling!

We can help you with a seamless new furnace installation if you are ready for an upgrade.

Call Oregon's beloved HVAC professional for regular furnace inspections to keep your family safe from any potential fire hazard.

Call Sunset Heating & Cooling | Electrical at (503) 500-5866

What Our Clients Say

Sunset went out of their way to help with my project and David was amazing. Great job and look forward to future projects.

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Caring, professional and helpful. Thanks for making things happen quickly and getting my Dear friend's heating back up and running in such a quick manner. You went above and beyond for a family in need and that is very much appreciated. Thanks from the whole group!

-Kristina K.

Jeremy was knowledgeable, personable, and took the time to explain things. Highly recommend his service.

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