Bad AC Capacitor Symptoms (Handy List!)

Ever experienced an air conditioner blowing warm air or showing what appears to be electrical problems – if so you could be seeing bad AC capacitor symptoms. Air conditioning systems have many components to keep the system working. A failure with a component signals homeowners the need for repair with symptoms like inconsistent performance. 

One such component is the capacitor. In this blog, we’ll cover the bad AC capacitor symptoms you need to know. We’ll also review what an AC capacitor does, how to test AC capacitors and how capacitors fail in an air conditioner.

Review: What Is an AC Capacitor? How Does an AC Capacitor Work?

The AC capacitor is a component within the outdoor condensing unit of an air conditioner or heat pump. It delivers power to the motor driving the air conditioning system. The capacitor delivers an initial energy burst to turn the system on when it’s time for a cooling cycle. Then it keeps it running with continuous electricity until the cycle is complete. 

The initial power burst is between 300 and 500 percent of the normal electrical amount required by the system. Once the air conditioner motor reaches proper operating speed, the capacitor limits excess power and supplies a steady amount for the duration of the cooling cycle. In some ways, it’s like a battery which stores energy and dispenses it during use.

What Causes Bad AC Capacitor Symptoms?

Problems with the AC capacitor prevent your air conditioning system from performing as it should. Bad AC capacitor symptoms are commonly caused by:

  • Overheated system circuitry
  • Short circuits in the cooling system
  • Power surges
  • Lightning strikes
  • Extremely high outdoor temperatures
  • Equipment wear and tear

How Long Do AC Capacitors Last?

Most will last 20 years. Again, if your AC over cycles, experiences extremes in temperature or surges or if the capacitor has a defective part, it won’t last that long. 

Issues Caused by Bad AC Capacitors

First, bad AC capacitor symptoms cause problems with your air conditioning system’s performance. A bad capacitor prevents the exterior unit from properly functioning, which hinders the cooling process as a whole. 

Second, improper voltage delivery to exterior unit components forces the system to work harder as it attempts to perform its job. 

Additional components often sustain damage due to a faulty capacitor. Finally, your energy bills may run higher due to the increased power demand to cool your home.

Bad AC Capacitor Symptoms Checklist

As a problem develops, the cooling system continues to run, albeit poorly, and homeowners may not notice right away. Other times, the main bad AC capacitor symptom a person notices is the air conditioner quits altogether.

These bad AC capacitor symptoms warn you of a cooling system issue. Contact us for air conditioning repairs if you notice:

  • Smoke or a burning smell from exterior air conditioning components
  • A humming noise from your air conditioner
  • Your air conditioner takes some time to start a cooling cycle once you turn it on
  • The air conditioning system shuts off at random
  • No cold air blows into your home while the air conditioner runs
  • The air conditioning system doesn’t turn on at all
  • Your energy bills are higher without explanation

How to Test an AC Capacitor

HVAC contractors use a tool called a multimeter to test AC capacitors. Also known as a multitester or VOM, it combines multiple measurement functions in one device. Most multimeters measure current, voltage and resistance. Analog multimeters use a microammeter with a spinning pointer to mark readings. 

Here’s a video showing the two types: 

When our technicians access the interior of your condensing unit to look for the source of the problem, these bad AC capacitor symptoms help professionals know to investigate the component further:

  • Cracks
  • Bulging
  • Oozing liquid from the capacitor and circuit board
  • Not enough charge when tested with a multimeter

Fix Bad AC Capacitor Symptoms with Sanborn’s Air Conditioning Services

If you experience any of these bad AC capacitor symptoms, call Sanborn’s right away for air conditioner repair. We get to work to diagnose the issue and quickly make needed repairs to limit discomfort to your family. 

If your air conditioner is ten years old or more, it may be time to consider a new AC installation. We are happy to send someone to take the appropriate measurements so your cooling system is the right size for your home. 

We offer free estimates and finance options so you can enjoy greater comfort and efficiency right away. 

Contact us today to schedule service or to request a free estimate for your Inland Empire home.