Uh-Oh, My Mini Split Froze – Now What?


Your mini split is a powerhouse of heating and cooling, a force to be reckoned with, but it can still freeze. Why’s that? Well, it still uses refrigerant, just like any other air conditioning system out there.

A mini split freezing up isn’t so different from a traditional AC freezing up. It shares similar causes and solutions. Let’s go over what causes mini split freezes so you know how to avoid it in the future and what you can do to maintain your mini split at home.

The Evaporator Coil Is Dirty

Your ductless mini split has an evaporator coil that pulls in warm air from your home. Over time, it can get dusty and impair performance. When the coil is dirty, the dust insulates it and interrupts the temperature exchange.

Cleaning your evaporator coil is necessary, but beyond that, you need to regularly clean out your air filter. With mini splits (especially from Mitsubishi), there are reusable screens that you can rinse out, dry, and then put back into your mini split. Do this often to keep the air flowing.

Run the Fan (Not on Auto)

Sometimes you can run the thermostat so low that your ductless mini split will simply freeze. It even happens with central AC systems. Turn the temperature on your thermostat up a little bit, then run the fan.

Put it on the “ON” setting, not the “AUTO” setting. When just the fan is on, it brings in warm air to help defrost your evaporator coil faster than if you let it sit idle.

There’s a Refrigerant Leak

If a mini split is leaking refrigerant at any point, it can result in freezing. Refrigerant and warm air flow work in tandem, and when there’s not enough refrigerant in the line, it expands and freezes.

Your mini split works on a closed-loop system. This means that refrigerant is put into a pipe that continually circulates through your unit. This process means that you never have to “top off” your refrigerant.

You do not have to top off a closed-loop system. If there are insufficient levels of refrigerant in the loop, it means there’s a leak somewhere. Less refrigerant means more room for available refrigerant to expand and freeze.

These leaks can be as small as a pinhole and very slow-going, but they will reach an apex when there’s just not enough refrigerant left in the line. When that happens and it freezes up, it can cause mechanical damage to the rest of your mini split. A technician has to repair the leak or replace the line before you can use your mini split again.

Your Mini Split Can Still Freeze

Even though your ductless unit has its differences from your standard central air conditioner, it can still freeze up just the same. It can be caused by leaks, dirty evaporator coils, and bad airflow.

Now that you know what you can do to prevent this issue from popping up again, make sure you get to it and do everything in your power to keep your ductless mini split from freezing. Don’t skip out on those annual maintenance appointments, either.

Contact HB Energy Solutions for all your energy needs. HB Energy Solutions delivers peace of mind.

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