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The Signs and Causes of a Broken AC Unit

It’s a big inconvenience when you have a broken AC unit. It could even be a dangerous situation if your AC breaks when it’s very hot or cold outside. That’s why it’s so important to get the problem fixed as quickly as possible. Of course, that requires determining what the problem is, so that it can be properly addressed.

It’s important to note that sometimes, AC units have problems that don’t cause obvious symptoms. The main thing you might notice is a gradual increase in your monthly utility bills. This is because an AC with worn-out or broken components can’t run efficiently. It may keep limping along, using more and more electricity as it struggles to keep up with demands on the system until it finally breaks completely.

Some AC problems are simple enough to figure out and fix on your own. Others are more complex and need fixing by a professional. Either way, the first step is knowing the signs that your AC unit is broken. Fortunately, several common things typically go wrong with AC units. This makes it easier to figure out what it might take to get your AC running smoothly again.

Troubleshooting AC Unit Problems

Troubleshooting your AC unit is something you can do on your own, to a certain extent. It’s simple for most homeowners to check whether the thermostat is on, for example, or if it accidentally got switched to “Fan” instead of “Auto.” Many homeowners can check whether a switch needs to be flipped at the breaker box. Most can replace their own AC filters each month.

When you have a broken AC, a heating and cooling specialist is the best person to conduct a comprehensive check of your AC unit to determine what’s wrong. A professional can also schedule annual AC maintenance check-ups to inspect your entire AC system. These check-ups help to extend the life of your AC because a pro can spot potential problems before they turn into bigger, more expensive repairs.

People tend to experience several different problems with their AC units over time. To troubleshoot these problems, let’s take a look at common AC issues and what causes them.

Troubleshooting Common AC Problem #1: AC Won’t Turn On

Sometimes, the first sign that you have a broken AC is when you turn on the AC at the thermostat, and nothing happens. No humming or whirring sound indicating that the system is starting up; no air blowing out of the vents. When this happens, it could be caused by several different things.

It could be a tripped circuit. This is common in older houses when there are too many appliances running at the same time. It can also happen after a storm if there are power surges. Try checking the main electrical panel in your home. If any of the switches are set to OFF, switch them back to ON to reset them. Wait 15 minutes, and then try turning on the AC again.

If that doesn’t fix the issue, it could be that your thermostat isn’t working. First, check to make sure it’s turned on and set to Cool. Next, make sure that it is set to a lower temperature than the temperature inside your house.

If it’s 75 degrees inside your house, for example, and your AC is set to cool your home to 76, it won’t kick on when you turn it on. This is because its internal thermometer won’t signal a need to cool down your home when it’s already cooler inside than what the thermostat is set. The thermostat could also need new batteries if it is battery operated.

Clogged air filters can also cause the AC not to turn on. AC filters should be changed out (or cleaned if you use the reusable kind) at least once a month. If you live with pets that shed or in a place with lots of dust or pollen in the air, you might need to change out your filters even more often.

Sometimes, the problem is something more complex. If you’ve checked the simple things and your AC won’t turn on, it’s time to contact a professional.

Troubleshooting Common AC Problem #2: AC Blows Out Warm Air

If your AC turns on but only blows warm air, the first thing to check is the simplest: Is the thermostat set to the correct mode and settings? It should be set to Cool, not Heat or Off, and to Auto, not Fan.

Dirty air filters can also cause your AC to blow out warm air. Dust, hair and other debris will clog the filter, blocking the flow of air through your home’s cooling system. If dirty air filters are causing the problem, installing new, clean filters should fix the issue.

There are other, more complicated reasons why your AC might blow out warm air. For example, it could mean the AC unit has a refrigerant leak. This can happen as the metal parts of your AC that come into contact with the refrigerant start to erode over time. The eroded metal allows tiny amounts of refrigerant to escape into the air. Refrigerant leaks can also happen when there’s an actual crack somewhere in the system.

Refrigerant is not something that homeowners should try to touch or refill on their own. Furthermore, an ongoing refrigerant leak can cause bigger problems with your AC. If you think your AC has a refrigerant leak, turn it off and contact a professional immediately. Continuing to run your AC with a leak might wind up damaging the compressor.

Frozen evaporator coils can cause your AC to blow warm air. Head outside to look at your AC condenser unit. If the evaporator coils are frozen, you might be able to see actual ice on them. You might also notice dirt and debris on or inside the unit. You might see extra condensation on the unit or notice an unusual level of humidity inside your home.

Other possible causes of an AC blowing warm air include a faulty compressor and a break somewhere in the air ducts. These issues are complicated to diagnose and fix, which is why a professional should address them.

Troubleshooting Common AC Problem #3: AC Making Strange Noises

Another common sign that you have a broken AC is when it starts making a strange noise. It might be a loud noise or a quiet one, but if it’s new and unfamiliar, that’s a sign that something is going wrong.

A grinding or squealing noise could mean there’s a problem with the fan motor or belt inside the AC unit. A banging noise could indicate a problem with the compressor, such as loose parts rattling around inside. A humming noise could mean an electrical issue involving the contactor relay switch.

These noises mean it’s time to call in a heating and cooling specialist. Electrical problems especially need to be dealt with as soon as possible, since they can present a fire hazard. Since your AC is a system made up of many different parts and components, ignoring a problem and continuing to use the AC can lead to bigger problems in the future. A professional can find the problem and make all needed repairs.

Can You Replace Just the Outside Unit?

When their AC breaks, people sometimes ask the pros, “Can you replace just the outside unit?” Air-conditioners have both indoor and outdoor components that work together as a system. Replacing your AC can be a major undertaking and very expensive to do. It’s tempting to want to replace just the outside unit, especially if that’s the source of the problem. This is not a good idea, however.

Your AC unit should last about 10 to 15 years. It could easily last longer than that if you maintain it well. When the AC breaks, replacing just the outdoor unit is not a good idea because it’s like replacing half of a faulty system. The new outdoor unit will be in good shape, but its efficiency will lessen the age of the rest of the system. Any failing components in the indoor unit will cause extra strain on the outdoor one. This will greatly shorten the life of the brand-new condenser.

That’s why it’s better to replace the whole AC when it’s time for a new unit. Though it costs more upfront, it will actually save you money over time—both in repairs and on your monthly electricity bill. An AC that can run at peak efficiency costs less to run since it uses less power. It also costs less over the long term since it is less likely to need expensive repairs.

Maintaining your AC over its lifetime is the best way to extend its life as long as possible. Fortunately, AC maintenance is surprisingly simple. Easy steps like changing out the air filters at least once a month and making sure your vents aren’t blocked go a long way.

It’s also a great idea to hire a heating and cooling professional to conduct annual or bi-annual HVAC checkups. These visits from a pro will ensure that your AC system stays clean and in peak working condition. It will also help to reveal problems early on before they develop into something much bigger and more expensive.

ABC Can Repair or Replace Your Air Conditioning Unit

Head these common air conditioning problems off at the pass with a regular maintenance schedule. Make sure you clean the air filter and coils regularly and change the air filter as needed. Plan for a thorough check of your AC unit on an annual basis, and have it done before the hot summer months to make sure you can address any problems without too much suffering. Contact the professionals at ABC to learn more about how we can help keep your air conditioner running smoothly.

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