4 Common Problems With Ductless Mini-Split Heat Pumps

Ductless mini-split heat pumps have become increasingly popular in recent years, thanks to their efficiency and flexibility in tailoring the size of the unit to your specific needs. However, like any other type of heating and cooling system, ductless mini-splits can experience a variety of common problems. 

Here are four of the most frequently reported issues:

1. Poor Airflow

Ductless mini-splits rely on good airflow to function properly. If the airflow is restricted, it can cause the system to overheat and shut down. This problem is often caused by dirty air filters or blocked air intakes, so it’s important to keep both clean. Change your air filter at least once every three months and check the air intakes monthly to make sure they’re clear of debris.

Depending on the model of your ductless mini-split, you may also have an outdoor unit that needs to be cleared of snow, leaves, and other debris. Mini split repair experts also recommend checking your system’s user manual to find out how often you should clean your unit and what type of maintenance it requires. In some cases, you can fix small problems like this on your own. 

2. Leaking Refrigerant

A leak in the refrigerant line is one of the most serious problems that can occur with a ductless mini-split. If left unchecked, it can lead to complete system failure. Leaks are usually caused by damage to the lines or improper installation. When the refrigerant leaks, it can cause the unit to work harder to cool or heat your home, which increases your energy bills.

If you think you have a refrigerant leak, it’s important to call a mini-split repair expert right away. They will be able to locate the leak and repair it before it causes any further damage. An efficiently-running mini-split should not use more than about 20% of the refrigerant it was originally filled with. 

3. Frozen Coils

The coils in a ductless mini-split can sometimes freeze up, particularly during the winter months. This problem is usually caused by low refrigerant levels or poor airflow. You can thaw frozen coils by raising the thermostat’s temperature or increasing the unit’s airflow. Once the coils are thawed, you should check for leaks in the refrigerant lines.

If you find that your coils are regularly freezing, it’s a good idea to call a mini-split repair technician. The good thing is that the latest mini-split models have a built-in defrost cycle that can help prevent the coils from freezing. A timer or thermostat usually controls this feature.

4. Thermostat Problems

Problems With Ductless Mini-Split Heat Pumps


Issues with the thermostat are one of the most common problems with ductless mini-splits. If the thermostat is not working properly, it can cause the system to overheat or shut down. Thermostat problems are often caused by incorrect wiring, a dead battery, wrong operating mode, or dust buildup on the sensor.

  • If you’re having trouble with your thermostat, the first thing you should do is check the batteries. If they’re dead, replace them and see if that fixes the problem. 
  • Also, make sure the thermostat is in the correct operating mode. If it’s not, you may end up cooling or heating your home when you don’t need to.
  • Another common issue is dust buildup on the sensor. This can cause the thermostat to give inaccurate readings, leading to problems with the system. 

If you’re still having trouble with your thermostat, it’s best to call a mini-split repair technician. They will be able to diagnose the problem and fix it quickly.

Preventative Maintenance is Key

To avoid having any major issues with your ductless mini-split heat pump, ensure that you are proactive with preventative maintenance. This means scheduling professional tune-up services to ensure that your system is running properly and efficiently. During these tune-up services, your technician will:

  • Inspect the air handler and evaporator coils
  • Check for any signs of refrigerant leaks
  • Test the thermostat to ensure it is accurate
  • Lubricate all moving parts
  • Clean the outdoor condenser unit

By keeping up with regular maintenance, you can help prolong the lifespan of your ductless mini-split heat pump and avoid any major issues or breakdowns.

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