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5 Reasons Why Your Air Conditioner Won’t Turn On

Jun 14, 2019

Air Conditioning Heating & Cooling
A digital nest thermostat that was supplied and installed by romaniuk heating for one of their customers.

A broken air conditioner may seem like a minor nuisance, but for children, pets, seniors, and other people who are sensitive to heat, this can be a serious issue. Plus, Alberta can be prone to some intense heatwaves, which can make homes feel more like saunas if they don’t have an effective AC unit.

So, if your air conditioner isn’t turning on you’re going to want to determine the cause and get it fixed before you’re stuck in an uncomfortably hot home.

There are a number of reasons why an air conditioner won’t turn on. In some cases, you might be able to fix it yourself be performing some simple air conditioning maintenance and repairs.

Here are the top five reasons why your air conditioner won’t turn on, and what you can do to get it back up and running.

There’s a Problem with Your Thermostat

First, make sure your thermostat has power. If it’s battery powered, check the batteries and replace them if needed. You’ll also want to check for a blown fuse and make sure the wires leading from the thermostat are intact. Rodents have been known to eat through wires, which can stop your AC unit from receiving signals from the thermostat.

Assuming your thermostat has power, the next thing you should do is check and make sure it’s set to COOL mode. You’ll also want to check to see if the temperature is set at least 3 degrees below the current room temperature. This may seem obvious, but you’d be surprised how many times this is the reason why an AC unit won’t turn on. It’s the first thing any air conditioning repair tech will check, so you might as well cross this off the list.

The Filter is Clogged

Every air conditioning unit is equipped with a filter that’s designed to catch dust and debris to prevent it from spreading throughout your home. If the filter becomes clogged even the most industrial AC units will stop working.

If you start experiencing problems with your air conditioner the filter should be one of the first things you check. Make sure the air conditioner is turned off before removing the filter (an AC unit should never run without the filter). If you see an accumulation of dust and dirt it will need to be changed or cleaned.

Some AC units have filters that need to be changed, while others have filters that can be cleaned. Consult the owner’s manual if you’re unsure what kind of filter your unit uses. If you notice any tears, holes, or other damage the filter should be changed regardless.

Filters that can be cleaned should be vacuumed or washed with warm water. You may also want to mix some baking soda into the water while washing it to remove any odours. Make sure the filter is completely dry before reinstalling it. Be careful not to damage the filter while cleaning it, or else you’ll have to buy a new one.

To prevent your filter from getting clogged, make sure to check it every 1-3 months.

Your AC Unit is Low on Coolant

Air conditioners work by passing air through a cooling system that rapidly lowers its temperature. This is done via coolant, a fluid or gas that is especially good at absorbing heat. The coolant flows through the system and removes heat from the cooling chamber, then deposits it outside.

Coolant eventually runs out over time, and it can also decrease due to incorrect installation or a leak. Every air conditioner has a manufacturer recommended charge for coolant level. If this charge isn’t met your air conditioner could start to malfunction or stop working altogether.

The lack of cold air or high energy bills may indicate low coolant levels

Coolant levels can’t be checked without a licensed HVAC repair technician, but there are a few signs, besides your AC unit not turning on, you can watch out for that may indicate that your coolant is low.

The first is a lack of cold air. It goes without saying that if your unit is low on coolant then the air isn’t going to get cooled as much as it used to. You may notice that the air coming from your air conditioner isn’t as cold as it once was, or it may start to take longer for your house to get down to your desired temperature. Both of these are signs that you may have a coolant issue.

Higher energy bills could also be a sign that you’re AC unit is low on coolant. Because it takes longer to cool your house with less coolant your air conditioner will have to run longer and work harder, resulting in more energy consumption.

Of course, if your AC unit isn’t turning on it’s not possible to know if it’s not generating cold air. However, you can check for ice build-up. When coolant levels are low, the evaporator coil gets too cold which causes ice to start to form around the coil and the surrounding components. If you notice any ice in and around your air conditioner it’s a good chance your coolant needs to be recharged.

If you suspect your AC unit is low on coolant, call a licensed air conditioning repair technician.

The Circuit Breaker’s Been Tripped

An air conditioning system uses a fair amount of power, meaning the load on your property’s electrical system increases every time your unit turns on. This can often can trip the circuit breaker, especially if the air conditioner hasn’t been used for a long period of time.

A circuit breaker is a safety measure designed to limit the amount of electrical flow going to household components. When the flow gets too high, the circuit breaker is tripped to prevent the component from being overloaded. Without a circuit breaker, you could be at risk of damaging your appliances or experiencing an electrical fire if anything were to go wrong.

If your air conditioner isn’t turning on it’s a good idea to see if the circuit breaker was tripped

So, if your air conditioner isn’t turning on it’s a good idea to see if the circuit breaker was tripped. Locate your circuit panel and check the circuit for your air conditioner. If it’s been tripped make sure it’s fully in the “off” position before flipping it back on.

Try turning your air conditioner on again. If it turns on without any issues, and the circuit breaker isn’t tripped, then everything is fine. It was likely just a momentary power surge, possibly from a thunderstorm.

If the circuit breaker is tripped again when you try and turn on your air conditioner do not attempt to reset it. Something is likely wrong with the wiring and you’ll need to call an HVAC repair technician to have a look at it.

Your AC Unit Has Overheated

If electrical devices become too hot it can lead to damage, burns, or even fires. This is why many devices are designed to shut down if their internal temperatures become too high. This is what’s known as overheating.

Most air conditioners have this same safety feature built in, so it’s possible that if your unit won’t turn on it’s because it’s overheated. There are a few different reasons why this might happen.

The first two reasons have already been covered in this blog. A dirty air filter and low coolant levels can both cause overheating. See above to learn how to rectify these problems.

Another issue that can cause overheating is dirty condenser coils in your outside AC unit. These coils carry coolant that has absorbed heat from your inside unit and then dump that heat outside. If the coils are dirty your essentially adding extra insulation to the coils, making it harder to release the heat. If you find the coils are dirty, try cleaning them with a coil cleaning spray.

Finally, check for any excess dirt, debris, or vegetation on or around your outdoor AC unit. Clear away anything that may be causing it to overheat.

Is Your Air Conditioner Still Not Turning On?

If you’ve performed all the air conditioner repair troubleshooting described above and your unit still isn’t turning on make sure to contact a licensed air conditioning repair technician. There are a number of other reasons why your air conditioner may be malfunctioning, and the professionals at Romaniuk are happy to help.

If you have any question or concerns feel free to contact us. One of our team will be ready to assist you.