AC Capacitor Failed? Keep Your System Starting Smoothly
The capacitor is the unsung hero of your air conditioner. When it fails, your system cannot start. Learn the warning signs, why they fail in Portland, and how Efficiency Heating & Cooling replaces them safely.
Emergency service available during summer heat waves across the Portland metro area.
Owner & Lead HVAC Technician
Quick Answer
Five Signs Your Capacitor Just Failed
Outdoor unit hums but the fan and compressor do not start.
AC starts, immediately stops, and tries again repeatedly (hard starting).
Fan blades spin only when pushed with a stick (never do this with power on).
Capacitor looks swollen, leaking oil, or has a ruptured top.
Breaker trips during startup even though components seem intact.
If you suspect capacitor failure, turn the system off and call us immediately. Running the compressor without a healthy capacitor can cause irreversible damage.
Why Capacitors Fail in Portland
Capacitors rarely fail at convenient times. In the Portland metro, rapid temperature swings, voltage fluctuations, and months of seasonal inactivity put unique stress on these components. Understanding the common failure causes allows us to recommend upgrades that extend system life.
Heat and Electrical Stress during Heat Waves
When Portland temperatures jump into the 90s, AC systems cycle frequently. Capacitors handle high inrush currents during each start, degrading faster during extended heat events.
Power Surges and Voltage Fluctuations
Lightning, grid switching, or utility brownouts send spikes through HVAC circuits. Capacitors absorb excess voltage and can fail prematurely.
Age and Wear
Most capacitors last 7-10 years. Systems that spend long months idle accumulate internal corrosion. When the cooling season begins, capacitors fail under renewed load.
Incorrect Replacement Part or Installation
Using the wrong microfarad (µF) rating or failing to secure wiring leads causes overheating. DIY replacements often make matters worse and can void warranties.
Contamination from Moisture or Debris
Outdoor capacitors exposed to rain, ants, or debris corrode. Keeping covers tight and clearing vegetation preserves the component.
How Professionals Replace Capacitors Safely
- Shut off power at the disconnect and main breaker.
- Discharge the capacitor safely with insulated tools — only trained technicians should do this.
- Remove mounting strap, note wiring positions, and install an OEM-rated capacitor.
- Inspect contactor, fan motor, and compressor for damage caused by repeated failed starts.
- Test the system for proper amperage and microfarad readings before restoring operation.
Prevent Future Capacitor Failures
Capacitor Failure FAQs
Restore Reliable AC Starts Today
Efficiency Heating & Cooling arrives with OEM capacitors, insulated tools, and the expertise to ensure your compressor and fan motors stay protected. Call now to get your system running smoothly again.