When your HVAC system isn’t working the way it should, a faulty capacitor could be the culprit. We see it all the time in homes across Denham Springs—especially during those hot, muggy Louisiana summers. Knowing how to check capacitor function safely and effectively can help you spot issues early, before they lead to bigger problems. At Summers Comfort Heating & Air, we’ve helped countless homeowners troubleshoot these components, and we’re here to walk you through it.
What Does a Capacitor Do in an HVAC System?
Capacitors store and release energy to help start and run motors in your AC or furnace. Without a working capacitor, your system may not start at all—or it might short-cycle, hum, or blow warm air.
In homes throughout Livingston Parish, we’ve seen systems act up simply because of a swollen or leaking capacitor. That’s why it’s so important to understand how to check capacitor performance if your system’s behaving oddly.
Signs Your Capacitor Might Be Failing
Here in Denham Springs, we get our fair share of capacitor-related service calls. Some of the most common signs include:
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AC or furnace won’t start
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A loud humming sound near the unit
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Fan not spinning
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Blown fuses or tripped breakers
If you notice any of these symptoms, it’s worth learning how to check capacitor function before assuming the worst.
How to Check Capacitor: Safety First
Before doing anything, turn off the power to your unit at the breaker. Capacitors hold a charge even after the system is off, so you don’t want to take any risks.
We always tell our customers around Denham Springs to proceed with caution—or better yet, call a pro. But if you’re set on a DIY route, at least wear insulated gloves and follow these steps closely.
Tools You’ll Need to Check a Capacitor
Knowing how to check capacitor issues starts with having the right tools on hand:
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A multimeter with capacitance settings
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Insulated screwdriver
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Safety gloves and goggles
Once you’re ready, go ahead and locate the capacitor—usually found in the outdoor AC unit or inside your furnace cabinet.
Discharge the Capacitor First
Before testing, you need to safely discharge the stored voltage. Using an insulated screwdriver, bridge the two terminals to neutralize the charge. Be careful—not doing this can cause a nasty shock.
How to Check Capacitor with a Multimeter
Set your multimeter to the capacitance setting (usually marked with “μF”). Then, connect the probes to the capacitor’s terminals. Compare the reading with the rating printed on the capacitor.
If the reading is more than 10% off the listed value, the capacitor is failing. This simple test is at the heart of how to check capacitor condition.
When to Call a Professional Instead
Even though checking a capacitor is doable for some, we don’t always recommend it. For many of our Denham Springs customers, it’s safer and faster to let our techs at Summers Comfort Heating & Air handle it.
We’ve seen systems get damaged from improper testing or handling. If anything feels off or you’d rather not take the risk, we’re always just a call away.
Replacing a Bad Capacitor
If your capacitor is toast, it’s time to replace it. But make sure the replacement has the same voltage and microfarad rating. Otherwise, you could end up causing more harm than good.
We keep these parts stocked in our service vans throughout Denham Springs and can often replace them the same day.
Don’t Ignore the Signs
Learning how to check capacitor health can save you money and prevent breakdowns. But if you’re not 100% comfortable, don’t go it alone. Summers Comfort Heating & Air is proud to serve homeowners throughout Denham Springs with honest advice and fast service.
Give us a call if you’re seeing signs of a bad capacitor—or just want a second opinion. We’re always happy to help keep your system running strong.
