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The shiny, cylinder-shaped battery among the jumbled mass of wires inside an air conditioner’s outdoor unit is the capacitor - one of the most important components of the entire HVAC system. It is responsible for energizing the air conditioner's motors. If this stops functioning properly, the entire HVAC system can stop working eventually.

What does an AC capacitor do, exactly?

Air conditioner’s motors need an initial jolt of electricity to run successfully and an AC capacitor stores and provides that electricity through powerful bursts that get your unit revved up. Once the air conditioner starts running, the capacitor reduces its energy output. However, it still supplies a steady current of power until the cycle finishes. They are important because air conditioners are high-powered machines that require a lot of energy and the facility's wiring simply can't provide the adequate amount of power needed.

What are different types of capacitors?

Depending on HVAC systems, there are mainly two types of capacitors found in the outdoor unit:

  • Start Capacitors: These are designed to deliver the energy an air conditioner's motor requires to start the cooling cycle. 
  • Run Capacitors: These capacitors step in after the initial jolt is provided by the start capacitors. They store and release the energy needed to keep the motor going and the AC blowing.

Some HVAC systems come with a dual capacitor. As the name suggests, these types of capacitors work like a combo pack that provide initial spark for the system to start and then supply a consistent flow of electricity to keep it running. They offer a lot more convenience, save space in the unit and are easier to replace.

When to replace an AC capacitor?

Here are some of the common signs that a capacitor is faulty and needs replacement:

  • The HVAC system either would take time to begin a cooling cycle or just won’t start at all
  • The HVAC system randomly shuts off on its own
  • The HVAC system is running but isn't cooling
  • The HVAC system is making humming noise during operation
  • Burning smell or smoke can be detected from the HVAC system
  • Energy bills are unreasonably high

There are several reasons why a capacitor would fail. Some these reasons include:

  • Damaged capacitor due to debris buildup,
  • Overheated capacitor due to extremely hot temperatures,
  • Wear and tear over a long period of time,
  • Short circuits in the HVAC system,
  • Power surges.

Looking to replace your faulty HVAC capacitor?

Get in touch with one of our HVAC experts at (877) 776-8228 to seek help in finding the right type of capacitor for your HVAC system. Our experts will analyze all the factors and help you determine which capacitor you would require for your unit. You can also check out our extensive range of Supco Capacitors.