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Many of our service calls are very simple: a blown capacitor. This is good for our customers because capacitors are comparatively inexpensive and quick to replace.

The part that is bad for homeowners is the simple fact that capacitors are a little bit like light bulbs. It might last 3 days. It might last 3 months. It might last 3 years. And there is absolutely no way to tell.

What Does a Capacitor Do?

Start capacitors give a jolt to the system to get the compressor and fan motor going. Run capacitors provide the oomph to keep the system running. They might be little, but without them, your unit is essentially dead.

Why Do So Many Capacitors Fail?

Capacitors blow for several reasons:

  • They become overheated by the sun (rooftop units are particularly susceptible to this)
  • They become overheated by the unit running too long and hard (this happens a lot during the summer months)
  • Power surges (including slight fluctuations in the electrical grid)
  • Lightning strikes
  • They wear out due to age and use

If you think your capacitor may be failing, it is imperative it is caught and replaced early. Running your unit with a failing capacitor can cause major (and expensive) damage. A dead capacitor can take out a motor or compressor with it, and possibly even cause the unit to fail entirely.

But How Do I Know if My Capacitor is Failing?

You probably won’t know, but we will! Preventative maintenance is the key to getting ahead of potential issues. Mode’s Fan Club is only $19.95 per month (for one unit) and that includes two preventative maintenance visits per year. One inspection can cost $150-$200…you can do the math. During these check-ups, we will inspect all aspects of your comfort system, including your capacitors.

There are a few signs of possible capacitor failure that homeowners can look for in between check-ups to (although there can certainly be other causes to the below):

  • The compressor struggles to start and then shuts off quickly
  • The unit starts and stops over and over
  • The AC is not blowing cold air
  • A humming noise
  • A clicking noise
  • Your system is performing differently than it previously had been

If a Capacitor is Such a Simple Part, Can I Replace it Myself?

We do not suggest that homeowners ever attempt to replace a capacitor themselves. The capacitor stores an electrical charge and contains hazardous oil. This is one piece of equipment best left to the HVAC professionals.

As always, if you have any questions about any part of your HVAC system, do not hesitate to contact Mode Comfort & Air Quality at 804-481-6633 or admin@modecomfort.com.