Lennox Air Conditioner Problems: 7 Common Issues (Must Read)

It’s pretty inconvenient if your air conditioner stops working on a hot summer day.

But, before you lose your cool, remember that complications and problems can occur regardless of brand, and there are things you can do to get your air conditioner up and running again.

Continue reading if you find yourself in this situation with your Lennox AC.

Lennox Air conditioners Problems: 7 Common Issues (Must Read)

Here are 7 common problems with Lennox air conditioners, along with their causes and solutions.

This is not to say that if you buy or own a Lennox air conditioner, you will have these problems.


These are the most commonly experienced problems.

Not too dissimilar to other air conditioner brands.

Lennox AC not cooling

From time to time, Lennox air conditioners can stop cooling the air they blow out

If your Lennox Air Conditioner is not cooling, not blowing cool air it’s likely to be a clogged air filter or defective thermostat.

However, you don’t need to worry, as reading the causes and solutions below might help you solve the issue.

Possible solution(s):


If your Lennox air conditioner is blowing hot air, the thermostat may have been set to “heat” by mistake. If this is the case, it’s a simple remedy that you can do on your own.

Simply turn the thermostat to “cool” and observe if the air conditioner starts to blow cool air once more.

Check the thermostat and make sure it is set to “cool” and at the proper temperature. If it needs new batteries, replace them.

Check the thermostat and make sure it is set to “cool” and at the proper temperature. If it needs new batteries, replace them.

Dirty Filter

A dirty air filter can lead to a dirty evaporator coil, even though air filters have nothing to do with air temperature.

There may not be enough free airflow to allow for efficient cooling operation if the evaporator coil becomes blocked with dust and debris.

Debris build-up from a filthy air filter can cause frozen evaporator coils.

Although you may believe that “frozen” equals “cold,” the frozen coils actually obstruct the flow of cool air, causing warm air to flow from the running engine instead.

Depending on the environment, filter type, and home, air filter change should be done every 30-60 days by the owner.

Setting a monthly reminder to check the condition of your air filter is recommended.

Lennox AC won’t power on

If your Lennox air conditioner is not turning on it’s likely to be a tripped circuit breaker.

Before you call a technician check if there is a blown fuse or a tripped breaker, If the fuse is found to be burnt out, replace the burned-out fuse and reset the circuit breaker to fix the error.

Possible solution(s):

  • When it comes to an unresponsive AC, the problem is usually a loose power cable or a tripped circuit breaker. So, make sure the power cable and the circuit breaker switch are both in place, and your AC might start to work. If this doesn’t help, reset the AC using the GFCI on the power cable.
  • If the quick fixes mentioned above don’t seem to work, the problem may be of a more serious nature, as the components could be faulty. However, you will need to call a professional to deal with this matter.

Lennox AC not blowing air

If your Lennox air conditioner turns on but doesn’t blow out any air, it’s likely to be a clogged air filter or defective thermostat.

Possible solution(s):

  • Remove the filers with care and gently clean them, removing any dust on the filters.
  • If the AC fan blades are not able to rotate, the AC won’t be able to blow out air. Debris and a broken fan axle are two common reasons behind this issue. To check if your AC fan is in working condition, open the unit and remove any debris inside the fan while fixing the loose axle. 
  • If the fan blades appear to be in working condition already, chances are the AC’s fan motor is broken. To test it, open the unit and turn the fan manually. If the fan rotates with resistance, you will need to replace the motor. 

Lennox AC produces an unpleasant smell

Rarely this happens, but Lennox AC producing an unpleasant smell is typically caused by mold or refrigerant leak. 

A refrigerant leak is likely if your mini-split smells like fish, or vinegar or has a sweet odor. A lack of chilled air is another tell-tale sign that you don’t have enough refrigerant.

If you’re dealing with this issue, it’s best to use some of the solutions mentioned below as soon as possible.

Possible solution(s):

  • If your AC has been spreading an unpleasant smell, it could be due to the presence of mold. After all, the humid internal environment of an AC is the perfect place for mold to grow. You will need to contact a professional to get rid of the mold for you.
  • If mold isn’t a problem and your AC is still spreading a bad smell, your Lennox AC might have an issue with its components. Overheated parts can easily spread a burning smell. Additionally, a gas leak can produce the smell of rotten eggs. To fix faulty components, call in a professional.

Lennox AC temperature inaccurate

If your Lennox AC hasn’t been keeping the temperature maintained at the value you set, it’s likely to be a faulty thermostat.

The good news, this issue can be dealt with if you read the following causes and solutions.

Possible solution(s):

  • The thermostat is responsible for regulating the temperature. If this part is broken, you will not be able to change the temperature and might even harm other components. However, a thermostat can be quite complicated to test and fix, so you’ll need a professional to do the work for you.
  • If the thermostat is working fine, the compressor might be broken and will have to be replaced. Additionally, you can also check for a refrigerant leak.

Lennox AC is not responding to the remote control

Lennox air conditioner’s remote is not working it’s likely to be an issue with the batteries,

Continue reading the possible causes and solutions to find the fix.

Possible solution(s):

  • The reason behind an unresponsive AC is typically a lack of power in the controller. So, replace the remote control’s batteries and test if it works. 
  • The main control board of the Lennox AC has an infrared receiver to receive the signals coming from the remote control. If this receiver fails to work, your AC will not respond to the remote control. So, if your remote control is in working condition, replace the main control board to fix the issue.

Lennox AC producing noise

If your Lennox AC is making more noise than normal it’s probably being caused by debris being stuck inside the appliance. 

However, there are several ways you can fix this issue.

Possible solution(s):

  • Typically, the reason behind noise is debris stuck in the AC. So, open up your AC unit and check for debris in the fan, filter, and other areas, removing it thoroughly. 
  • The fan motors contain lubricated ball bearings. However, over time, this lubrication can decompose, causing the bearings to produce noise when the fan rotates. If that’s the case, replace the motors for your AC fans. 

If your Lennox air conditioner is spewing heated air, making hissing or gurgling noises, or has ice on the refrigerant line best to turn it off and call a technician 

How long do Lennox air conditioners last?

Lennox air conditioners typically have a lifespan of 15 to 20 years.

An air conditioner that is used more frequently than average will naturally experience more wear and tear than a unit that is used less frequently.

So, to extend the life of your air conditioner, keep it in good working order at all times.

Lennox air conditioners any good?

Yes, Lennox air conditioners are very good. Lennox is a well-known brand in the air conditioning industry.

After all, Lennix not only develops innovative features for its products that are energy efficient but also ensure that they are reliable for years to come.

As a result, Lennox is unquestionably a good brand of air conditioners.

Pros and cons of Lennox air conditioners

Here are some pros and cons of Lennox air conditioners. 


  • Customers seeking energy-efficient system
  • Reputable brand
  • Those who live in harsh climates and have high utility bills


  • Can create high levels of noise
  • Higher priced than its competitors


If you need an air conditioner, Lennox is the brand to choose from. However, sooner or later, you will encounter some difficulties.

In that case, the solutions listed above will come in handy.

So, keep them in mind and keep your Lennox AC in good working order at all times.

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