A/C Won’t Turn On? Here Are 12 Things to Check Before Calling a Technician

Summer in Edmonton is the best…until it gets too warm! An air conditioning unit can make your home more comfortable when the temperature spikes, but it requires regular maintenance and care.

When an A/C unit isn’t turning on, it can be frustrating. We recommend keeping your user manual handy to give you a head start when investigating issues. The manual will show you where all the parts are located, so you can assess and get the cool air flowing again.

The most common problems with air conditioning units usually involve dirty air filters, an incorrect power supply, or a refrigerant leak. Luckily, there are many things you can do to fix these problems. Here are the top 12 things to check before calling a technician.

Check Airflow from Vents

The first step in assessing your A/C unit is to check for improper airflow. Feel around the vents to see if the unit is blowing warm air and listen for strange noises or dry air sounds. This may provide clues to check the outside unit or investigate potential power issues. 

You can perform a garbage bag airflow test to see how much air is coming through the vents. 

Check Your Circuit Breaker Panel

If your A/C isn’t turning on, it could be because there’s no power running to the unit. One reason for this could be that the circuit breaker has shut off. This happens when there’s too high of a demand for electricity on that circuit, from using too many appliances at once, or from one older appliance on the circuit hogging a lot of power. 

If you suspect this is the case, head to your breaker box and see if there is a blown fuse. You’ll see one of the toggles looks different than the rest, and you’ll need to turn it off and turn it back on to reset the breaker.

If the circuit your A/C is on keeps shutting off, you may need to rearrange your appliances so there’s enough electricity to go around.

Test Your Thermostat

Your thermostat could be malfunctioning! First, check to see if it needs batteries or is broken. If it won’t kick on, you might have an electrical problem.

If you’ve never calibrated your thermostat, you’ll need to. This signals the A/C system to turn on. Need a hand? We can help. 

Check Your Refrigerant

Refrigerant, sometimes called coolant or Freon, is necessary for an air conditioning unit to work properly. If your A/C isn’t cooling your home, or you hear a hissing sound near the unit, you could have a leak. Refrigerant doesn’t have a taste or smell, and if you’re exposed to it for a while, you could experience refrigerant poisoning, so it’s important to remain vigilant. 

Due to the dangers of this chemical compound, it isn’t something you can top up yourself. A licensed technician must do this task. Contact us if you suspect refrigerant is the problem.

Uncleaned Air Filters

When air filters get dirty, airflow is obstructed. A dirty filter causes your unit to work harder, meaning it uses more energy (and your electricity bill gets more expensive). If your air filters are full of dirt and debris, condensation can’t drain through the drain lines. Instead, the water droplets freeze in the coils, leaving you with layers of ice.

It should be pretty easy to spot the filter. It’ll likely be on the side of the unit in a vertical position. You can pull it out and take a peek. We recommend replacing filters every 90 days, or more often if you have allergies or pets. Air filter sizes and positions in the unit may differ, depending on the model or brand of your A/C. 

A/C Unit Breakdown

A capacitor gives the initial jolt of power to the unit at the beginning of each air conditioning cycle. Once the fan is running at full speed, the capacitor reduces its energy output. The capacitor can fail for a few reasons. Physical damage to the unit, overheating, and the capacitor’s age can all impact its effectiveness.

Electrical issues can also cause problems. If an improper voltage runs to the unit, the capacitor can fail. You can check the voltage with a multimeter or voltmeter. You must shut off the power supply to stay safe while running the test. If you’d like assistance with or are not confident about doing this, we can help. Give us a call if you’d like us to perform a check.

Clogged Condenser

The condenser line in your A/C unit can also get dirty. Dust, mold, and dander can get trapped inside. The good news is that it’s pretty easy to clean.

To stay safe, you’ll want to shut off the power to the unit before cleaning. Lift the lid on the unit, and then use white vinegar and a wet/dry vacuum to get the debris out of the line. You may find using a brush to scrub helps with any stubborn particles. 

Unclean or Leaky Air Ducts

The air ducts in your home pull warm air to the A/C system so it can be cooled. If the ducts are dirty, leaky, or have a clog, air can’t move the way it needs to. Leaks can happen due to tears made by rodents, or if there were mistakes during installation. If you feel uneven cooling, it is likely due to warm air escaping through holes in the system.

If you spot a leak yourself, you can seal it with HVAC tape. It might be tricky to find the imperfections, though. That’s where we come in! If you need a hand with duct leakage, give us a call.

Inspect On/Off Switches

Most air conditioners have a master on/off switch. For a lot of outside units, it’s outdoors in a separate box, mounted to the house. If you’ve recently had work done on your air conditioning system, the technician might’ve left the switch in the off position. 

For indoor units, you might find the master power switch near your furnace. In some cases, it looks just like a light switch. Someone may have turned it off without realizing it. 

Malfunctioning Evaporator Coils

So many parts in an A/C unit are prone to build-up. The evaporator coil is one of them! Sometimes, the coil will completely freeze up. This happens when condensation forms on dust, dirt, dander, and other debris and then freeze while the A/C is running. When that frost builds up, it causes the coil to stop cooling the air, resulting in warm air coming out of the vents. 

The coil will need to thaw. We recommend turning the unit off and giving it a day to warm up. If that doesn’t fix it, it may be a refrigerant level issue, or something else more complex. One of our expert technicians can diagnose and fix the problem.

Check A/C Lifespan

Each unit is different, but a good rule of thumb is that an air conditioner lasts for about 12 to 15 years. So, if your unit is getting to be that age, you might want to consider upgrading to a newer version so your home can stay comfortably cool. 

Inappropriate A/C Unit Size to Power Outlet

If your air conditioner isn’t turning on, it could be a power supply issue. All air conditioners have their own electrical requirements. Small units, like a 115 volt with a 15 amp requirement, can run off of a standard outlet, but anything larger will need its own outlet and circuit to operate. 

Size is a consideration when planning the power source, but you’ll also want an air conditioner that is the appropriate size for the space you want to cool. When we say size, we don’t mean the dimensions of the unit, we mean BTUs or British Thermal Units. BTUs show how much energy is being used to remove heat from your home in one hour.

To determine what size of air conditioner you need, you will multiply the room’s length by its width. Then, multiply by 25 BTU. That will give you the minimum cooling capacity of what your air conditioner should have. 

If you’re looking for guidance with this step, we’re happy to help! Our expert technicians know air conditioners inside out and can offer suggestions for what will work best in your home. Give us a call today.