What Is An HVAC Capacitor And Why Do They Go Out? | BHI Plumbing Heating & Air Conditioning
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15April

One of the most common elements that fail when the AC stops working during the summers is the Capacitor. Firstly, you need to know what a capacitor is and how it works before knowing why it fails.

Essential Element Of Your HVAC’s System

The primary role of your Capacitor is to store electricity and work as a rechargeable battery. So whenever required, it can supply energy to the motor that is connected. Some of the essential capacitors include start and run capacitors. The start capacitor provides some additional voltage that the compressor needs to get the fan motor compressed or to get it started. On the flip side, the run capacitor gives the energy essential to run the cycle. Both the cooling and heating systems need a dual-run capacitor that connects the compressor and the fan. The furnaces also use a single-run capacitor which is attached to the blower motor.

Reasons Why A Capacitor Goes Bad

Ideally, the capacitors are sensitive to overheating, and it can be caused mainly due to the sun. It is primarily for air conditioners that are installed on rooftops. It can be more than 150 degrees on hot summer days, and electrical overheating can cause the unit to function at optimum capacity for a longer duration. Capacitors usually fail on the hottest summer days. It would help if you also considered setting the thermostat a little higher on summer days to keep the HVAC from overheating. You can use reflective blinds on east and west-facing windows if you want to improve energy efficiency.

The Capacitor can also fail if there are any power surges. Additionally, if there is a lightning strike from the thunderstorm during summers, then the HVAC’s Capacitor’s electrical system may get overloaded and burn out. The weaker power surges may cause damage to the capacitors a few years down the line. The fluctuations in the electrical grid also tend to cause inconsistent ripples. This will mainly affect simple and large appliances in the house when you switch them off.

The thunderstorm outrage tends to cause a power outage, and a power surge happens when the power is back, which damages the Capacitor. You can protect the AC and the capacitors from power surges and ensure you install an HVAC surge protector.

Age Matters

Like a chargeable battery, a capacitor’s ability to store and release energy tends to decrease with time. It is inevitable to know that capacitors will wear out sooner or later. If you come across a failing capacitor, it is straightforward and cost-effective to fix. If your AC continues to work with failing capacitors, then they tend to cause severe issues to the overall system.

Failing and Going Bad?

People are curious to know how the failing capacitors affect the HVAC. It is one of the most common reasons to have some preventive maintenance regularly. It is all about checking the HVAC system’s electrical components; besides having a licensed technician examining the capacitors, a few ways to learn that a capacitor is not functioning work. A capacitor can be affected if the air conditioner’s compressor has problems starting, and then it shuts off in no time.

Additionally, if you hear some humming or clicking sounds from the HVAC unit, it can be due to bad capacitors. Also, if the air conditioner isn’t running well, then it might be possible the capacitors might not be performing well.

Don’t Ignore The Problem

One of the biggest problems is people tend to ignore the problem of the HVAC capacitor. It might be tempting to put off the maintenance service if the AC is not working correctly; however, that is not a good idea. If the AC is not working, the first thing you should do is to get it fixed by a licensed technician. If the Capacitor is not working well, the repair is relatively inexpensive. All you need is an experienced technician to replace it with another capacitor. You also shouldn’t opt for DIY methods when it comes to replacing the capacitors. The motor attached may get overheated and burn out if the Capacitor isn’t connected or working correctly.

Capacitors are often ignored, and they tend to be the root cause of most HVAC problems. It is always a good idea to take a second opinion from a service technician if the first one gives you a list of things to replace in the system. Make sure it is not the Capacitor that has malfunctioned before replacing the rest of the parts.

Billy Henley
Billy Henley is the Vice President of Operations for BHI Plumbing, Heating & Air Conditioning. Before becoming vice president, he worked six years in the field as a service technician and has over ten years of experience working in the industry. Billy often shares his knowledge about plumbing and HVAC issues on industry publications.