Air Conditioner not turning on? Follow this Checklist

Last Updated on 15 February, 2024 by Sourav Roy

You know what they say ‘Home is where the heart is’. Ever wondered why this emotion is felt so strongly? Because no place in the world can make us feel as comfortable as being at home. Well, an air conditioner adds substantially to this feeling. Any obstacle with this appliance can be haphazard, as it provides a sense of solace. If your air conditioner is not turning on, you don’t have to exchange it for a new one. In most cases, you can fix the damage by knowing the nitty-gritty of the problem.

Air Conditioner not turning on


My page has everything you need to know and do when your AC is not turning on. Here’s a detailed checklist for you. By the end of my blog, there are high chances you may not need to seek expert help for every little issue. Excited? Let’s begin.


Major Elements of an Air Conditioner

Before we get to the reasons and solutions for the AC unit not turning on, let us know a little about the appliance. Here are a few common terms you must be well acquainted with and how they play a role in the smooth functioning of an air conditioner.


1. Refrigerant

Ac Refrigerant

Refrigerant, also known as the coolant, is a pivotal element to the cooling appliance. It carries all the hot air from the inside to the outside. It absorbs the heat, changes the state from gas to liquid and then pushes the heat outside.


2. Compressor

Air Conditioner Compressor

The compressor is designed to pressurize the refrigerant, thereby raising the temperature. Once the gas is squeezed tightly, it heats up instantly. The refrigerant temperature must certainly be more than that of outdoors to dispense all the heat out. The component works towards changing the low-pressure refrigerant to a high-pressure refrigerant.


3. Condenser coil

Air Conditioner Condenser coil

The condenser coil is the outside AC unit. It is designed to receive all the high-pressure refrigerant that comes from the compressor. The condenser facilitates heat transfer to the outdoor air. It plays a big role in releasing all the heat. Once that’s done, the refrigerant then flows to the expansion valve.


4. Expansion valve

Air Conditioner Expansion valve

Even though the refrigerant has dispersed heat, it is still too hot to move into the evaporator coil. That’s where the expansion valve plays a role. It is known as a metering device and cools down the refrigerant completely. The expansion valve also controls the amount of refrigerant entering the evaporator coil and changes its state from liquid to gas.


4. Evaporator coil

Air Conditioner Evaporator coil

Here’s one of the most important components of an air conditioner. All the heat from inside the room is picked up and dispersed here. The refrigerant cools down at the evaporator coil completely.


5. Air filters

Air Conditioner Air filters

Now that you know the entire process of getting cool air, do you think it’s enough? What of the foreign substances present in the air? Air conditioners are equipped with filters to eliminate all harmful elements from the refrigerant.

All the components mentioned above play a role in delivering clean and pure air from your air conditioner. Remember, any minor issue with even one of them can break the chain of facilitating cool air. It can also lead to your AC unit refusing to turn on. However, there’s more to this problem. Let’s find out.


Is your Air Conditioner not turning on? Reasons & Solutions

1. Reason: Blocked Air Filters

Air Conditioner Blocked Air Filters

Every home appliance requires regular cleaning for smooth functioning. So, why not an air conditioner? But, before I get to that, I want to know how often you clean the filters of your air conditioner? Pull up your socks if you aren’t doing so. Cleaning the air conditioner filter should be a part of your routine cleaning. Do you know why? Besides the AC unit not turning on, a clogged air filter can cause various other complications.

  • Overheating of the air conditioner: If the air filters are blocked, your air conditioner will have to work harder. In this case, there will be more pressure on the appliance. Therefore, there are high chances of the unit overheating.
  • Unclean air: If the filter is not clean, how will the unit deliver clean air? The primary goal is to get cool air, but obviously, you want to breathe in pure air as well. If your air filters are clogged with dirt and debris, it will block the airflow or let that out in the air it blows. Therefore, take no chances.
  • Lowers energy efficiency: I have already mentioned above how blocked air filters can make the appliance work harder. It means it will consume a lot more energy than it should in the usual case. So yes, the energy efficiency is sure to go down.
  • Impact the cooling capabilities: One of the most prominent problems is that a dirty filter can impact the cooling capability of the appliance. In this case, your room is not going to cool the way it should.

Solution: The deal here is that you can either call a professional to clean the filter or even do it yourself. Well, I would recommend you to do it by yourself. It is super simple.

  • Step 1: Remove the filters.
  • Step 2: Run it through warm water.
  • Step 3: Soak it in the water for a while.
  • Step 4: Let it dry out naturally.
  • Step 5: Place it back.

Have you tried this, and it has not helped? Replace the filters in that case.


2. Reason: Refrigerant Leakage

Air Conditioner Refrigerant Leakage

Refrigerant leakage can be one of the reasons why your AC is not turning on. Refrigerant is a cooling fluid that does the main job of eliminating all the heat from the air. Over some time, you may notice some cracks in the air conditioner coil. It could cause the refrigerant to leak. And the leakage can lead to a substantial shortage. A refrigerant shortage can certainly lead to your appliance not turning on or not cooling enough.

Solution: The refrigerant level in the appliance should match the exact level mentioned by the manufacturer. Therefore, sort this out by seeking professional help. But please do not do it yourself, as there’s a lot of space for things to go wrong.


3. Reason: Blown Fuse

Air Conditioner Blown Fuse

A blown-up fuse can be one reason for your AC not turning on. You can do a multimeter test to know whether the fuse is working perfectly or not. A blown-up fuse generates a humming sound from the outdoor AC unit. Therefore, you cannot miss this issue by any chance.

Solution: First, unplug the AC unit and the main power. Remove the blown-out fuse and replace it immediately. I wouldn’t recommend you to fix this yourself unless you have enough experience.


4. Reason: Ice build-up

Air Conditioner Ice build-up

The air condenses and creates a liquid when it gets too cold. This liquid continues to get colder and freezes, causing inadequate airflow. The entire process leads to ice build-up. There is another reason for the formation of ice. If the air filters are dirty, they cause the water droplets to freeze and eventually result in an ice layer.

Solution: In the case of clogged filters, you know you have to clean or replace them immediately. In the first situation, here is what you got to do.

  • Step 1: Turn off your air conditioner unit.
  • Step 2: Disconnect it from the power source.
  • Step 3: Let all the ice melt.
  • Step 4: Clean the coil.
  • Step 5: Make sure the AC becomes completely ice-free.


5. Reason: Faulty Thermostat

Air Conditioner Faulty Thermostat

A malfunction in the thermostat can certainly affect the performance of your air conditioner. Any hindrance with the thermostat can result in your AC unit not turning on. If the thermostat becomes outworn, blank or broken, you must act upon it immediately. The thermostat also needs timely battery replacements. If you notice the AC compressor not working, but the fan is running, then a wrong temperature is set on the thermostat.

Solution: Number one, ensure the thermostat is rightly set. Number two, pay attention to when the battery needs replacement. Number three, monitor the working of the thermostat. Set the temperature five degrees less than the room temperature. If you can feel cool air coming out of the vents, your problem is solved. However, if the air conditioner is still not turning on, turn off the thermostat and turn it on again. In the case of the last situation, you need to reset the thermostat.

  • Step 1: Turn off the appliance.
  • Step 2: Turn off the circuit breaker lined to the AC unit.
  • Step 3: Wait for a minute or two.
  • Step 4: Turn on the circuit breaker, then the appliance.
  • Step 5: Reset the thermostat.


6. Reason: Loose wiring

Air Conditioner Loose wiring

Loose or faulty wiring can be a significant reason for any issue in the air conditioner. There are wires inside the unit and connecting to the outside unit. They play an important role in the functioning of the air conditioner. Over a while, the wirings or power cord can wear out. They can also get damaged in case of any power outage. But don’t panic; you can easily fix it.

Solution: Fixing the wiring by yourself can be risky. You can be a victim of an electric shock. Thereupon I would recommend you get it fixed by an electrician. In an extreme situation, you may need an HVAC professional to check the damages.


7. Reason: Flawed Motor

Air Conditioner Motor

If there is any issue with the motor, you will hear a grinding noise once you turn it on. The air conditioner motor is sealed for protection against debris, dust, water and air. In case you don’t service it regularly, the seal can come out. Also, the oil used in the motor for lubrication can seep out once the seal comes out. Without this oil, the motor can stop working. If the motor does not work, how will the air conditioner work?

Solution: Figuring this out can be a bit tricky. Should you repair the motor or replace it? First, you need to check if there is any life left in the motor to repair it. If yes, then what are the damages? Is it worth it? Will replacing the motor make more sense? Are you confused? Let me tell you how to decide upon this. If repairing the motor will cost you half the amount of replacing it, it makes sense. If it costs you more than 50% of buying a new one, please do not waste your money fixing it.


8. Reason: Tripped Breaker

Air Conditioner Tripped Breaker

A tripped circuit breaker is a noteworthy reason for the AC unit not turning on. It could happen due to overload or some other appliance being too old or faulty or high energy consumption. No matter what the reason is, the breaker supplying power to the air conditioner will trip. There is no way your AC will turn on then.

Solution: Find the circuit breaker of the air conditioner and turn it off completely. After a few minutes, you can turn it on. However, if it trips again, then take it as an indication that something is wrong. Maybe it’s happening due to high or heavy voltage. In any case, taking expert help would be a smart move.


9. Reason: Dirty Condenser

Air Conditioner Dirty Condenser

Just like the air filter needs cleaning, so does the condenser. Since the condenser unit is placed outside, it is easily prone to mould, debris and dirt. Without regular servicing, the condenser can get filthy, which can lower the efficiency of the appliance. In addition, the dirt on the condenser will lead to the unit tripping the beaker and result in the air conditioner not working.

Solution: When I say cleaning the condenser, I mean proper and deep cleaning. Illegitimate cleaning of the condenser can be worse than not cleaning it at all. It can damage the compressor coil fins and the appliance brutally. Therefore, take no chances doing it yourself. Instead, sign a contract with a professional and get it done regularly.


10. Reason: Unclean evaporator coil

Air Conditioner Dirty evaporator coil

When dander and dust accumulate on the evaporator coil, it can hamper the efficiency of the appliance. In the long run, it will result in your air conditioner breakdown. Therefore, you cannot neglect this component either.

Solution: The solution to this problem kind of remains the same. Periodic cleaning and maintenance is a must. Nevertheless, you can do it yourself as well. A mild detergent solution and a clean rug can do the magic for you. You can also use a toothbrush to scrub off some parts.

Those were the ten common reasons for your air conditioner not turning on.


Tips to Maintain an Air Conditioner

Tips to Maintain an Air Conditioner

Take care of your appliance, and it will reciprocate. So here I am with a few easy-going tips on how you can maintain your Air Conditioner.

  • Keep a constant check on the refrigerant level
  • Keep the area under the AC neat and uncluttered
  • Hire a professional HVAC service
  • Keep the unit clean
  • Keep the air filters clean
  • Keep the compressor covered in winters
  • Ensure that the evaporator coil, condenser, drainage pipe and expansion valve are in the best condition.

Once done with this checklist, you are good to go!


One Last Thought

So, is your air conditioner not turning on? Now, you know the culprit behind it and how to get rid of it. The appliance can last you for a long time if you maintain it well. If your appliance is more than 10-15 years old, maybe you should consider replacing it instead of repairing it. To get your hands on a new one, you certainly should be well versed with the options available in the market.

If you’d like, you can refer to some of our blogs that have a lot of information about buying ACs:-

Well, in case your air conditioner is fairly new, I’m sure you’d like to familiarize yourself with the obstacles that can come your way. To know more, check Common problems with an AC – and how to solve them!

You are now all ready to beat the heat gracefully! Summers won’t bother you anymore.

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