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Is Your AC Making a Clicking Noise?

February 28, 2023

Communication is the key to any good relationship, and an AC clicking noise could be a sign that your friendship with your AC is headed south! The professionals at Patrick Riley Cooling, Heating, & Plumbing can help translate these sounds to keep you running, and cool, for years to come.

A soft click or two when your air conditioner starts up is its way of saying, “Here I go, time to get to work,” and that’s perfectly normal. If you notice your outdoor or indoor AC making a non-stop clicking noise, something could be wrong with your system that is affecting its ability to keep its cool.

An electrical issue usually causes an audible clicking noise, but this isn’t always the case. There could be a variety of other reasons that you’re hearing a clicking noise coming from your AC system, including

Below, we’ll talk about each of these issues in detail and show pictures of the inside of an AC unit so you can get a better idea of why your AC is clicking at you, how you may be able to fix it, or whether you need to call an expert for help.

Patrick Riley Cooling, Heating, & Plumbing’s expert technicians are always here to make sure your AC keeps its cool. We’ve been speaking the AC language fluently for over 30 years, so we have solutions for all types of clicking or clunking noises—and we deliver them with upfront and fair pricing.

What Does a Working AC Sound Like?

For an outdoor AC unit to be in working order, there should be no clicking, buzzing, or other unusual sounds—aside from when the machine powers on. However, not every air conditioner sounds exactly the same. Even though an AC contains many moving parts, a working unit should only make a light hum, along with other calming sounds, such as the whirring of a fan.

An indoor or outdoor AC making a clicking noise indicates that something from inside the machine is out of place or not working as intended. Below are details on four scenarios that might relate to your clicking air conditioner.

Clicking Noise Culprit #1: Faulty Contactor

Where to find a faulty contactor: Outside, located inside of your outdoor AC system.

What it sounds like: Faulty air conditioner contactors make consistent humming, buzzing, or “chattering” noise in your outside AC.

Prior to your capacitor dying, you will likely hear a soft but consistent humming noise from the side of your AC unit.

Your contactor plays the role of “operator” when it comes to your AC system. Your thermostat calls for cool air, and your contactor is in charge of turning on your outdoor AC unit.

If your contactor is worn out or not working as intended, your outdoor AC unit won’t be able to receive a signal from your thermostat. This can result in your AC making a clicking noise—the system is trying to start but can’t.

Here’s a word of warning: This piece of your AC unit can store a high voltage. Attempting to repair or replace a contactor without the appropriate precautions could lead to electrocution or damage to your AC system. The professionals at Patrick Riley Cooling, Heating, & Plumbing are standing by to replace your contactor safely. Call 602-286-0027 or schedule an appointment online if you think you may have a bad contactor.

Clicking Noise Culprit #2: Dead Capacitor

Where to find a dead capacitor: Outside, located on the side of your outdoor AC unit.

What it sounds like: Prior to your capacitor dying, you will likely hear a soft but consistent humming noise from the side of your AC unit.

In essence, the capacitor in your outdoor AC unit is a large battery that helps “start up” the cool air.

Just like any battery, capacitors lose their charge over time, and the clicking noise from the AC could be a sign that your unit doesn’t have the power needed to boot up.

Capacitors can also die out prematurely. If you’ve replaced your capacitor in the past couple of years, there’s a chance it might be defective.

If you think you may have a dead capacitor, reach out to a Patrick Riley HVAC expert for a successful AC repair and replacement.

Clicking Noise Culprit #3: Thermostat Issue

Where to find a thermostat issue: Inside your home, at your thermostat.

What it sounds like: AC relay clicking is an amplified and or long version of what you hear when your AC clicks on.

If your contactor and capacitor are humming the same healthy tune, then you're likely dealing with a thermostat issue, such as a broken relay or frayed wiring.

When your AC unit is running normally, you should hear a soft clicking sound when your thermostat tells your air conditioner to boot up. That noise comes from the relay opening to power on your unit. However, if the relay is broken or a wire is in bad condition, the relay will continue to open and attempt to send power to your AC despite an inability to start, causing an AC relay clicking.

Like the other audible issues, both of these repairs (broken relay or wiring issue) require the services of an HVAC technician, who can properly diagnose and solve the problem. If you think your thermostat is the culprit, reach out to Patrick Riley Cooling, Heating, & Plumbing to have an expert come and inspect the AC relay clicking in your Arizona home.

Clicking Noise Culprit #4: Loose Fan

Where to find a loose fan: Outside, located in the center of your outdoor AC unit.

What it sounds like: A loose fan typically sounds like a loud clicking or tapping noise.

A loose fan will definitely cause your outdoor AC unit to click. If a fan is what’s making noise in your unit, that means it’s doing more than just spinning. Either the fan blades can move along the shaft, or the shaft itself isn’t entirely screwed in.

If your fan becomes loose, it can hit the casing of your outdoor AC unit while it’s running and create a kind of clicking or tapping noise. This causes damage to the inside of the unit and its blades. A loose fan can also be troubling, as it limits the cooling ability of your system overall.

This is an easy fix for an HVAC professional. The skilled technicians at Patrick Riley Cooling, Heating, & Plumbing can take your AC unit apart to determine if the belt can be tightened or if your fan blades need replacing, ending the outdoor AC clicking noise.

Need Help with Your AC System? Reach out to Patrick Riley Cooling, Heating, & Plumbing in Phoenix

AZ HVAC & Plumbing Service Area

If you’re regularly hearing an AC clicking noise similar to one of the issues above, you’ll need a professional to come and fix it. Schedule a repair today! We know our way around all kinds of cooling machines, and we’re fluent in all types of AC languages. Homeowners in Phoenix, Mesa, Chandler, and surrounding Arizona cities trust the quality of our work—whether it’s a furnace, HVAC, or plumbing repair.

Why Choose Patrick Riley

From your first call to us, communication is our priority! Our AC repair service representatives will walk you through what you can expect before, during, and after your tech’s visit so there are no surprises. We are industry leaders in AC troubleshooting and repair, specializing in AC clicking noises. We even have our very own company lab where we train our technicians, so you can trust that you’ll get expert service.

You’re not an AC unit to us—you’re our neighbor. Our friendly technicians all across Maricopa County will complete your HVAC repair quickly, efficiently, and to your complete satisfaction.

We’ll never leave you guessing about the cost—you can count on getting upfront pricing and answers to all of your questions. Sign up for a flexible AC payment plan, download a service coupon for this month’s savings opportunities, or consider a VIP Maintenance Plan for scheduled maintenance and exclusive discounts. We help alleviate the pressures that come with repairing the inside of an AC unit. Schedule your service today!

Originally published: July 29, 2020

Written by: Patrick Riley Cooling, Heating, & Plumbing

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By Ty Lindsay

Ty Lindsay is the Director of Field Operations at Patrick Riley | Isley’s and a 15-year veteran of the plumbing and HVAC trades. In 2010, Ty earned his Journeyman’s plumbing license. He became a Master Plumber five years later and earned his Journeyman HVAC technician’s license that same year. Ty’s breadth of knowledge in plumbing and HVAC includes both residential and commercial work. He’s been a loyal member of the Patrick Riley | Isley’s team since 2016.