Can a Mini Split Freeze Up?

You know that an air conditioner can freeze if it doesn’t have enough refrigerant. Since your ductless mini split system is capable of cooling (as well as heating), you wonder if the unit could suffer the same fate.

Although ducted and ductless systems are usually as different as can be, this is one thing they do share. Indeed, then, your mini split system could freeze.

What Causes a Mini Split to Freeze?

Let’s explain one scenario in which a mini split freezes in more detail.

Mini splits, like air conditioners, use refrigerant. Refrigerant is a type of chemical compound that can absorb heat and then send cool air through the unit. In the case of your mini split, those units are indoor air-handling units.

If you have a leak anywhere in your system this could potentially cause the pressure within the mini split system to drop quite rapidly. The coils will begin to lose temperature and can fall below freezing in some instances. Water vapor near the unit can latch onto the coils and cause them to freeze.

Here’s another scenario that can result in a frozen mini split. A dirty evaporator that is causing a backup in the system and creating a freeze!  It’s important to make sure evaporators stay clean for this reason.  Another reason could be a bad ambient sensor that is causing the mini split system to overwork thus creating a freeze.

This will make your mini split system blow air while failing to warm your home. The reason is that the mini split cannot pull heat from the air. Once the mini split thaws, it should begin working normally again.

How Do You Thaw a Mini Split?

Oh, darn. You realize now that your mini split coils must be frozen and that’s why they’re not working. You need to defrost the coils ASAP, but how do you do that?

Turn off your mini split’s thermostat. Begin running its fan mode instead. Although you might think this will only make conditions colder, by letting the fan operate for several hours, your mini split components should be effectively thawed.

You can check the mini split after an hour of running the fan and it could be defrosted, but it usually takes longer. If the coils were frozen solid, then you might have to keep the fan on overnight or even for 24 hours.

Tips for Preventing Mini Split Freezing

Your mini split coils have successfully thawed, but that wasn’t a fun experience. How can you prevent future instances of freezing? Here are our top tips.

  • When your mini split technician inspects the system, ask them to check the refrigerant levels.
  • They should also inspect the thermostat and the fan.
  • Every week, check the condensate drain to ensure it’s working as intended.
  • Once per month, take a look at your mini split filter and clean or replace it as necessary.