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Why is My Mini Split Not Working?

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Like anything, your mini-split is bound to malfunction at some point, and when it does frustrations can arise. After all, who wants to come home from a long day of work to find their mini-split isn’t cooling or heating? Well, don’t panic just yet because we’ve got you covered with this comprehensive troubleshooting guide. From identifying the issues to finding solutions, let’s get your mini-split up and running again.

Understanding Mini Split Basics

A ductless mini-split is an energy-efficient HVAC system that offers targeted heating and cooling for individual rooms called zoning. Mini-split heat pumps consist of an outdoor compressor/condenser and an indoor air-handling unit that is either on a wall or ceiling. Mini-split systems are different from central AC, which uses ductwork to distribute conditioned air throughout the entire home. With mini-splits, each room has its own unit that can be controlled separately. This makes them a popular choice for homes without existing ductwork or rooms that require individualized temperature control.

Mini-Split Troubleshooting Guide

It’s essential to understand the common issues that may cause your mini-split to stop working correctly and if it is something you can fix yourself or need an expert to handle it.

Lack of Power

If your mini split isn’t turning on, the first thing to check is the power supply. Make sure to inspect the electrical panel and ensure the break is on. Also, check the batteries on your remote and change them if needed.

Dirty Air Filter

A clogged air filter can restrict airflow and cause your mini-split to overwork, resulting in poor performance. Changing your air filter is a quick and easy DIY fix that often solves many mini-split issues.

Refrigerant Leak

Leaks in the refrigerant lines can cause your mini split to lose its cooling or heating capabilities. If the air coming from your mini-split has a sweet, vinegar smell then it is likely a refrigerant leak and it’s best to call a professional HVAC technician to handle the repair.

Sensor Malfunction

The sensor on your mini-split measures the temperature in the room and adjusts accordingly. If it’s not working correctly, your unit may not heat or cool effectively. Make sure the sensor on your mini-split is clean and properly attached. You may need to reposition or replace it if it’s not functioning correctly.

Thermostat Problems

Incorrect thermostat settings or a faulty thermostat can also cause your mini-split to malfunction. Check that your thermostat is set to the correct mode (cooling or heating) and temperature.


Unusual noise from your mini-split system could indicate a problem. Squeaking or grinding noises might suggest a faulty fan motor while gurgling sounds could point to a refrigerant leak or condensate pump issue. If your unit is making strange noises, it’s best to disconnect it and call a professional HVAC technician to avoid further damage.

Mini Split FAQs 

Why is my mini-split not cooling?

There could be a few reasons why your mini-split isn’t cooling. You may have a refrigerant leak or a clogged air filter, both of which hamper the cooling process. Another issue could be a malfunctioning sensor, which misreads room temperature and doesn’t cool the space effectively. A professional can diagnose the specific problem and suggest a solution.

Why is my mini-split not heating?

If your mini-split isn’t heating, it could be due to low refrigerant levels or a malfunctioning sensor that misinterprets room temperature. Incorrect thermostat settings can also prevent your unit from heating properly. It’s advisable to consult with an HVAC professional to pinpoint and resolve the issue.

How often should I clean or replace the filter in my mini-split?

Cleaning or replacing your filter regularly is crucial for the optimal operation of your mini-split. Generally, you should aim to clean your filter once a month and replace it every 6-12 months. However, this can vary depending on usage and air quality, so check your manufacturer’s guidelines.

What should I do if I suspect a refrigerant leak?

If you suspect a refrigerant leak, it’s best to call a professional HVAC technician. Refrigerant leaks can be hazardous, and fixing them requires specific tools and knowledge. Plus, it’s essential that your mini-split has the correct amount of refrigerant to function efficiently.

Why is my mini-split making a strange noise?

Odd noises from your mini-split can signal a problem. Squeaking or grinding sounds can indicate a faulty fan motor while gurgling sounds often suggest a refrigerant leak. If your mini split is making strange noises, disconnect it and reach out to a professional HVAC technician to prevent further damage.

How long do mini-splits last?

Mini-splits usually last between 10 to 15 years, with proper maintenance and care potentially extending their life to 20 years. This longevity is largely dependent on factors such as usage patterns, frequency of maintenance, and the environment in which the unit is installed.

Why does my mini-split keep shutting off?

If your mini-split system keeps shutting off, a common cause is a faulty thermostat or a problem with the power supply. A blocked condensate line or an overloaded circuit could also be the culprit. Regular maintenance and professional inspections can help identify and resolve these issues promptly.

How do I reset my mini-split?

Resetting your mini-split can often resolve minor issues. First, turn off the unit and unplug it from the power source. Wait for about 15 minutes, then plug it back in and turn it on. In some cases, you may want to go to the electrical panel and turn the breaker off, wait 5-10 minutes, then flip the breaker to the on position.

Can my mini-split be repaired?

Yes, a malfunctioning mini-split can often be repaired. Common issues like a dirty air filter or a thermostat problem can be fixed easily, while more complex problems like a refrigerant leak may require professional assistance. Regular maintenance can prevent most issues and extend your mini-split’s lifespan.

When to Call a Professional

While some issues with your mini-split system might be straightforward to diagnose and solve, many are complex and require a trained eye. Problems like refrigerant leaks, sensor malfunctions, or odd noises emanating from your unit are often indicative of deeper issues that necessitate a professional’s expertise. Attempting to fix these problems yourself could lead to further damage, creating more serious issues in the future.

Hiring a certified technician, like those at Jacobs, offers a host of benefits. Our consultants’ extensive training and experience ensure accurate diagnosis and efficient repair, preventing recurring issues. They’ll also ensure that your system operates safely and at peak efficiency, prolonging its lifespan. Professional technicians stay updated on the latest industry standards and regulations, guaranteeing the highest quality of service. When it comes to your mini split system’s longevity and performance, trusting a certified technician is a wise investment.

Preventing Future Mini Split Issues

Routine maintenance plays a vital role in the efficient performance and longevity of your mini-split system. Regular check-ups can prevent many common issues such as clogged filters, refrigerant leaks, and sensor malfunctions, ensuring that your system continues to heat or cool your space effectively. Maintenance activities like cleaning filters, checking refrigerant levels, inspecting for leaks, and ensuring sensors and thermostats are functioning correctly can significantly enhance your mini-split’s efficiency and extend its lifespan.

Regular maintenance can help detect potential problems early, allowing for proactive repairs that prevent more extensive damage and costly fixes down the line. A well-maintained mini-split also operates more efficiently, reducing energy consumption and thus lowering your utility bills. In this regard, investing time and resources in routine maintenance is not just a necessity, but also a smart financial decision. Remember, an ounce of prevention is worth a pound of cure, particularly when it comes to your mini-split system.

Mini-split HVAC Service in Portland

You depend on your HVAC system to work to keep your family comfortable. If you are looking for help troubleshooting your mini-split system, our consultants at Jacobs Heating & Air Conditioning can examine your system and determine what repairs need to be made. If you need mini-split maintenance or repair we are ready to help you save money and keep surprise breakdowns away. You can schedule your next tune-up and keep the stress and hassle out of maintaining your system. No matter what you need we’re always just a phone call away.

About the Author

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Amanda Jacobs, Internal Project Manager

Amanda Jacobs is an Internal Projects Manager and 3rd generation member of Jacobs Heating & Air Conditioning. She received her MBA from Seattle University and has worked for a leading HVAC training and consulting firm. When not talking HVAC on the Jacobs Blog, you can find her on the golf course or whipping up her famous vegan chili.