Why Does My Furnace Keep Blowing Fuses? Good To Know

In this blog post, we will study the reason behind the issue of blowing fuses of furnace systems in detail.

Is your furnace blowing fuses? 

There could be a variety of reasons behind the blowing fuses of the furnace such as accumulation of dirt in the air filter, an electrical short circuit, water leaks, a malfunctioning gas valve or blower motor.

Why Does My Furnace Keep Blowing Fuses

Common Causes of Blown Furnace Fuses

In order to tackle the common causes of blown furnace fuses, let me share with you some effective solutions that will help you keep your HVAC system running smoothly this winter. 

Air Filter Problems

Dirty air filters can really cause a blow-up! When they restrict airflow, the blower motor has to work harder resulting in a blown fuse. To avoid this, get a clean air filter on hand.

Neglecting your HVAC system leads to poor air quality, dust, and asthma/allergy triggers. So, replace old parts with higher MERV ratings for better use.

Invest in annual HVAC maintenance plans to keep your systems clean and running optimally. 

Electrical Shorts

Furnace fuses blowing out due to electrical shorts are an annoying issue. These arise when wires, breakers, or switches in the furnace’s circuitry don’t work properly. 

This can lead to an abnormal jump in power and blown fuses. Poor wiring connections, damaged internal components, or faulty thermostats can cause electrical shorts.

Prevent this by getting regular maintenance and inspection. Professionals can find frayed wires or damaged components that lead to too much current flow. 

Keep flammable items away from your furnace – as short circuits could lead to explosive accidents..

Gas Valve Malfunction

  • Furnaces are essential for keeping our homes cosy in winter. 
  • A blown furnace fuse is a typical issue homeowners face. This can be caused by a gas valve malfunction.
  • Reasons behind this malfunction include a clogged fuel line or a broken gas valve
  • The gas valve may not open fully and that results in inadequate heating output.
  • A faulty gas valve is a hazard, leading to carbon monoxide leakage or fire. 
  • Address any furnace issues with a certified professional right away. 

Blower Motor Issues

This extra resistance will make the motor work harder, and may lead to a blown fuse. 

Plus, if you run your furnace for too long, heat build-up can cause overheating of parts, and those pesky fuses will blow again.

Signs of Blown Furnace Fuses

To address the issue of blown furnace fuses, you need to know the signs that indicate that fuses have blown. 

If you hear strange noises or encounter heating problems, it could be a sign of blown fuses. 

Strange Noises

From banging to clunking, whistling to squealing, each noise can point to a specific issue. 

For example, 

A loud banging noise could mean a dirty burner or faulty ignition. A high-pitched whistling is observed.

Not all furnace issues are audio-related. Your home is not getting warm, even though the thermostat is on, that could point to electrical problems

Heating Problems

Heating problems can be majorly uncomfortable, especially during the colder months. A furnace can malfunction and cause various heating issues, from too little heat to none at all. Signs of blown furnace fuses are a common problem.

When a fuse blows, the heating system may not work or not work correctly. Tripped circuit breakers or a power surge can cause a fuse to blow.

Blown fuses can result in furnace malfunctions and make it stop working altogether. Replacing the fuse with new ones regularly is one option.

Checking wiring issues in the electrical circuits and connections between high-power-consuming equipment and other elements is important. 

Check that the wattage limits are not exceeded to prevent overloading and blowing out fuses.


Overheating is a major sign of blown fuses of a furnace. This means the current isn’t supplying the system properly, causing it to overwork and heat up. To avoid further damage, switch off the furnace and call a professional to repair it.

Don’t underestimate the impact of blown fuses – they can have huge consequences on your heating system. It can lead to sky-high energy bills due to overworking.


Short-circuiting is a typical issue that can happen to furnaces for various reasons. This occurs when the current avoids its usual path and flows through something else, leading to heat accumulation.

 This can cause blown fuses and major damage to your home heating system.

Short circuiting can be caused by several factors, such as loose connections or broken wiring. So, if you aren’t trained in electrical work, don’t try to fix it yourself.

  • If you notice any unusual noises or smells coming from your furnace, call a certified professional to inspect it.
  • Change your air filter regularly to prevent excess buildup and reduce strain on your furnace.
  • Keep the area around your furnace clean and free of debris to prevent any potential fire hazards.

Prevention of Blown Furnace Fuses

To prevent the problem of blown furnace fuses, you need to take necessary steps to ensure regular maintenance of your HVAC system with proper cleaning and replacing of air filters. 

Regular Maintenance

It is essential to have regular upkeep to avoid blown furnace fuses. 

Make sure your furnace is running well by taking these steps:

  1. Check air filters every month. When needed, clean or replace them.
  2. Clean blower blades twice a year to keep dust away.
  3. Inspect fan belts twice a year. Change if broken or worn out.
  4. Examine heating system components yearly.

Cleaning and Replacing Air Filters

Air filters are essential for preventing blown furnace fuses. To keep your furnace running, clean and replace air filters regularly. 

Here are four key points:

  1. Clean air filters monthly for proper airflow.
  2. Replace disposable filters every three months, or sooner if they’re dirty.
  3. Use high-efficiency pleated air filters for better performance.
  4. Keep track of filter changes to remember in time.

Checking for Water Leaks

Water leaks can cause furnace fuses to blow and give homeowners an unwelcome headache. To avoid this, it’s paramount to check for water leaks regularly.

Here are five tips to help you prevent blown furnace fuses:

  1. Check water supply lines and valves connected to the furnace.
  2. Examine the condensation pump and drain hoses for leaks and clogs.
  3. Look for any signs of moisture around the base or in the furnace cabinet.
  4. Listen for any sounds from the furnace that could point to an issue with water leakage.
  5. Investigate areas around your home where water pipes may be prone to freezing due to low temperature. Install insulation if needed.

Upgrading Electrical Wiring

Electrical wiring is a must-have for any home. Upgrading it can help you avoid blown furnace fuses and stay safe. 

Here’s a 5-step guide:

  1. Inspect the existing wiring.
  2. Choose the wire gauge and type that fits your needs and local building codes.
  3. Turn off power in the upgrade area.
  4. Replace old electrical boxes, switches, and outlets with new, safer ones.
  5. If unsure, hire a licensed electrician.

Repairing Blown Furnace Fuses

To repair blown furnace fuses with troubleshooting the following issues,

Troubleshooting the Issue

Furnace fuses that blow can cause great inconvenience and stop the furnace from working. 

To fix this issue, you have to follow some steps:

  1. Switch off the power supply and locate the fuse box.
  2. Check if any fuse has blown and if it matches the right amperage.
  3. Replace the fuse cautiously and switch on the electricity supply to check if it works.

Checking the Control Board and Circuit Breaker

When a furnace fuse blows, it’s an inconvenience. But, you can fix it! To do it effectively:

  1. Turn off power to the furnace before fixing.
  2. Look for any damage on the control board.
  3. Use a multimeter to check voltage entering and leaving the board.
  4. Press reset button firmly if there’s one in the circuit breaker box.
  5. Test the circuit breaker with a multimeter or test light.

Replacing Blown Fuses

When a furnace fuse blows, it is a nuisance. But this often happens in winter. If your furnace stops working, the fuse might have blown. 

Here is how to replace it:

  1. Turn off and unplug the furnace.
  2. Find the fuse panel close-by the furnace or in the main electrical panel.
  3. Spot the broken filament inside to find the blown fuse.
  4. Take out the old fuse and put a new one with the same amperage rating.
  5. Switch on the furnace and check if it works.
  6. If not, call an HVAC technician.

Hiring Professionals for Complicated Repairs

When it comes to repairing a furnace, most homeowners dread the task. 

Maintaining a Quality Furnace

Maintaining a quality furnace is key for an efficient HVAC system. Homeowners face issues like furnace blowing fuses. 

These can be costly to repair or even cause a fire hazard. To prevent this, air filter must be regularly maintained and water leaks checked. 

Dirt accumulation on parts such as blower motors or gas valves can also cause blown fuses. Therefore, timely professional maintenance and fixing of any strange noises is important.

Wiring issues like loose wires or short circuits can also cause blown fuses. Overvoltage and high-limit trips are other reasons. 


Therefore, taking action at the first sign of furnace issues can prevent costly repairs. Homeowners must prioritize maintaining quality heating sources during winter months. According to Grove City Heating & Plumbing Co., more than 50% of service calls received each year could have been avoided with regular maintenance.