Shocking Reason Why Your Air Handler Keeps Blowing Fuses (and How To Fix It)

Air handlers are essential components of your HVAC system, responsible for circulating air throughout your home. However, when they start blowing fuses repeatedly, it can be a frustrating and costly problem. This blog post aims to provide you with a comprehensive understanding of why your air handler may be experiencing this issue and offer effective solutions to resolve it.

Electrical Overloads: A Common Culprit

One of the primary reasons why air handlers blow fuses is electrical overloads. These occur when too much current flows through the circuit, causing the fuse to trip as a safety measure. Common causes of electrical overloads include:

• Oversized air handler: Selecting an air handler that is too large for your home’s needs can put excessive strain on the electrical system.
• Faulty wiring: Loose connections, damaged wires, or incorrect wiring can lead to increased resistance and current flow, triggering fuse blowouts.
• Dirty evaporator coil: A dirty evaporator coil restricts airflow, causing the air handler to work harder and draw more current.
• Frozen evaporator coil: When the evaporator coil freezes, it blocks airflow and can cause the compressor to overheat, leading to an electrical overload.

Mechanical Issues: The Silent Culprits

In some cases, mechanical issues can also contribute to air handler fuse blowouts:

• Seized blower motor: A seized blower motor prevents air from circulating, causing the air handler to overheat and blow fuses.
• Worn-out bearings: Worn-out bearings increase friction and can put additional strain on the motor, leading to electrical overloads.
• Unbalanced blower wheel: An unbalanced blower wheel can cause vibrations that damage electrical components and trigger fuse blowouts.

Capacitor Failure: A Hidden Problem

Capacitors are electrical components that store energy and help the air handler motor start up. When a capacitor fails, it can cause the motor to draw excessive current, resulting in fuse blowouts.

Compressor Problems: The Heart of the Matter

The compressor is the heart of the air handler, and its failure can also lead to fuse blowouts:

• Overheating: Compressor overheating due to refrigerant leaks, dirty coils, or a seized motor can cause fuse blowouts.
• Electrical shorts: Electrical shorts in the compressor winding can cause a sudden increase in current flow, tripping the fuses.
• Failed start capacitor: A failed start capacitor prevents the compressor from starting properly, leading to electrical overloads.

Other Potential Causes

Apart from the aforementioned reasons, other factors can also cause air handler fuse blowouts:

• Power surges: Sudden power surges can damage electrical components and blow fuses.
• Faulty thermostat: A faulty thermostat can send incorrect signals to the air handler, causing it to malfunction and blow fuses.
• Dirty air filter: A dirty air filter restricts airflow and can cause the air handler to work harder, leading to electrical overloads.

Resolving the Issue: A Step-by-Step Guide

If your air handler keeps blowing fuses, follow these steps to resolve the issue:

1. Check the air filter: Replace the air filter if it is dirty.
2. Inspect the wiring: Ensure that all electrical connections are tight and secure.
3. Clean the evaporator coil: Use a coil cleaner to remove dirt and debris from the evaporator coil.
4. Check the blower motor: Listen for any unusual noises or vibrations. If the motor is seized, it will need to be replaced.
5. Inspect the blower wheel: Check for any signs of imbalance or damage.
6. Test the capacitor: Use a multimeter to test the capacitor’s capacitance and resistance.
7. Check the compressor: Inspect the compressor for any signs of overheating or damage.
8. Call a qualified HVAC technician: If you are unable to identify or resolve the issue on your own, contact a qualified HVAC technician for professional assistance.

Troubleshooting Tips: Preventing Future Blowouts

To prevent your air handler from blowing fuses in the future, consider the following tips:

• Regular maintenance: Schedule regular maintenance to keep your air handler in optimal condition.
• Oversized air handler: Avoid installing an air handler that is too large for your home’s needs.
• Dirty coils: Clean the evaporator and condenser coils regularly to prevent airflow restrictions.
• Power surges: Use a surge protector to protect your air handler from power surges.
• Faulty thermostat: Replace a faulty thermostat promptly to prevent incorrect signals from being sent to the air handler.
• Proper sizing: Ensure that your air handler is properly sized for your home to prevent excessive strain on the electrical system.

Questions We Hear a Lot

1. Why does my air handler keep blowing fuses when I turn it on?

• Electrical overloads, seized blower motor, or failed capacitor can cause fuse blowouts when the air handler is turned on.

2. What does it mean if my air handler blows fuses only when the AC is running?

• Oversized air handler, dirty evaporator coil, or a malfunctioning compressor can cause fuse blowouts specific to AC operation.

3. How can I tell if the capacitor in my air handler is bad?

• A multimeter can be used to test the capacitor’s capacitance and resistance. A faulty capacitor will exhibit abnormal readings.

4. What happens if I keep replacing fuses in my air handler?

• Repeatedly replacing fuses without addressing the underlying cause can lead to further damage to the air handler and electrical system.

5. How much does it cost to fix an air handler that keeps blowing fuses?

• The cost of repair depends on the cause of the problem. Minor issues may be resolved for a few hundred dollars, while major repairs can exceed $1,000.