Mini-Split Unit Not Cooling?- How to Troubleshoot & Fix.

Hi! In full disclosure, we may earn money from companies (like Amazon) mentioned in this post if you make a purchase through our links. Thanks in advance for the support!

Mini split not cooling — How to fix the issue?

A not cooling mini-split can be a huge problem. Thankfully, it is not something that’s very hard to resolve. Your mini-split can stop cooling for a number of reasons, some of which you can fix yourself while for others you may have to send an SOS to your local AC repair service. Either way, you can expect a resolution fairly quickly.

In this post, we will discuss in-depth the most common reasons for a mini-split not cooling and their solutions. So, let’s get started.

As always we recommend getting a trained professional to perform any repairs on your Senville or other HVAC units.  If you would like to be connected to a local service provider please CALL FOR QUOTE: 1.855.920.1857 Or Request a service quote online here.

Or visit our state-by-state directory to find a list of mini-split HVAC companies in your area. 

Also, each system is a bit different. So you may want to check out our manufacturer-specific troubleshooting articles here for more information.

  1. The thermostat is not set correctly

When you first notice that your air-con is not doing its job properly, first take a look at its thermostat settings. Make sure it is set to cool. Now, wait for a couple of minutes to check if the AC is now blowing cool air. If so, the problem is solved!

If the problem still persists, try the other solutions listed in this post in the order they appear.

  1. Dirty air filter

The air filter is an important component of the indoor unit of your mini-split. It does the dirty but all-important work of keeping the components inside the indoor unit cleaner, which in turn ensures your air-corn operates efficiently.

How does it do this? By catching dust, dirt, and other airborne particles when they enter the indoor unit. Because the air filter is in the line of fire, so to speak, it can do with a bit of help from you every now and then. Without it, the air filter may get so dirty as to block airflow, resulting in your home not getting cool enough. In the worst-case scenario, it can cause the mini split to shut down.

If the thermostat is set to cool, but your AC is still not blowing cool air, it’s time to check and clean the air filter. Here’s what you need to do:

  • Switch off the AC
  • Remove the air filter (It is located in or around the indoor unit)
  • Clean the air filter and wait until it dries out
  • Insert the air filter back and power on the AC
  • Wait for a few minutes to check if this has made any difference

If the problem persists, you need to dig a little deeper to find out the cause.

  1. Blocked condenser unit

For your mini-split unit to work efficiently, both the indoor and outdoor units must be in top shape. If the condenser unit is blocked, your AC will struggle to provide you with the desired comfort.

To understand how a blocked condenser unit can impact the cooling of your home, it’s important to understand how a mini split works. Simply put, the indoor unit absorbs heat from the air inside your room and sends it to the outdoor unit. The outdoor unit — aka the condenser — condenses this hot air into cool air, which the indoor unit blows into your room, bringing the indoor temperature down to the desired level.

If the condenser is clogged, it will fail to properly condense the hot air into cool air. Therefore, make sure the outdoor unit has enough room to breathe by removing any dirt and weed that surrounds it. Next, carefully vacuum the condenser coil using a brush attachment. Alternately, you can gently rinse it with a hose.

Once you’ve cleaned the outdoor unit, check whether your system is working efficiently. If not, you probably need professional help.

CALL FOR QUOTE: 1.855.920.1857

Or Request a Service Quote Online

  1. Faulty Motor

A faulty or broken fan motor prevents your condenser from dissipating heat and in turn impacts your mini split’s cooling capacity. Fixing the motor of the fan is something that should be left to experts. Therefore, we recommend you contact your local AC service shop.

  1. Low refrigerant level

A refrigerant is a unique chemical compound that is necessary for your air conditioner. In simplified language, it absorbs the heat from your indoor space, providing a cooling effect for air conditioning. If your mini-split is low on refrigerant, its cooling capacity will be poor. Apart from low cooling, other signs of low refrigerant levels include ice formation on the evaporator coil and/or the discharge pipe, a bubbling or hissing sound, and a vinegar-like smell coming off your mini-split. Contact a certified HVAC technician to get the refrigerant refilled.

CALL FOR QUOTE: 1.855.920.1857

  1. Damaged compressor

The compressor is the most important component of a mini-split AC. It does the all-important job of managing the refrigerant flow between the unit’s evaporator and condenser. If the compressor is damaged, your mini-split will not be able to cool the indoor space. You will have to replace the faulty or damaged compressor.


As you can see, your mini-split may fail to provide sufficient cooling for multiple reasons, from simple issues such as a dirty air filter and thermostat not set correctly to more complex ones like a damaged compressor or low refrigerant level. If the DIY solutions listed above don’t work, call your local AC repair service. Certified technicians will inspect your mini-split air conditioning unit to find out the underlying cause and then will fix the issue so that your air-corn is able to run without any hiccups and provide the desired comfort.

Other Mini-Split Manufacturers Related Articles

Who makes carrier mini-split systems?

Who makes Lennox mini-split systems?

Who Makes Mirage Mini-Split systems?

Who Makes Klimaire Mini-Split Systems?

Who Makes York Mini-Split Systems?

Who Makes LG Mini-Split Systems?

Who Makes Air-Con Mini-Split Systems?

Who makes cooper and hunter mini-split systems?

Who Makes GREE Mini-Split Systems?

Who makes MrCool Mini Split Systems?

Who Makes Pioneer Mini Split Systems