When your air conditioner freezes up, it means your Chalmette home and family will be getting uncomfortably hot in short order. Repairing your frozen AC is urgent for another reason: frozen coils can seriously damage your air conditioner.

Properly maintained, your cooling system can give you more than a decade of service, so it may not be time yet to replace your current HVAC system. Here we’ll share some DIY steps you can take, and when it’s best to call in our friendly HVAC contractors. You may be wondering, “how did this happen? Why do AC coils freeze?” So let’s look at typical causes, consequences, and solutions related to an air conditioner freeze-up.

How Can a Frozen Coil Damage My AC?

While your evaporator coil is blocked with the ice, your AC’s blower fan continues trying to pull air through. This may keep your air conditioner from cycling off and on, as it normally would, placing great stress on the AC compressor. As the system overheats, the safety system should kick in and/or the electricity may cut off as the circuit breaker trips. Problems don’t end here, however, because the frozen coil begins to melt–and the resulting flood of water can damage anything nearby, such other HVAC components, electrical wiring, or a wall or ceiling.

What Happens When A/C Coils Freeze?

Here’s what goes on inside the AC coils leading up to a freeze.

When your air conditioner’s airflow drops or is blocked by something in the system, the refrigerant that circulates through the evaporator coil cannot do its job of absorbing and transferring heat energy. The refrigerant gets colder and colder and keeps condensing water. It soon goes below 32 degrees and that’s when ice forms on the coil.

In other cases, you may have a refrigerant leak, which can occur due to long-term vibration of the AC equipment. The leak causes low refrigerant pressure, which interrupts proper heat transfer and absorption in the system. The coil gets colder and colder, then freezes.

Common Reasons for Frozen HVAC Coils

So how did this happen? Poor or non-existent air flowing through the AC system is the most common cause. Here are the typical issues leading to an AC freeze:

  • Clogged and dirty air filter in your HVAC system, which leads to low airflow and a coil freeze (see the section above for more detail). This is why it is so important to check and change your air filter often. If you’re not certain how to do this, your HVAC tech can show you on your next HVAC maintenance call. The AC manufacturer’s recommendation about the filter replacement timing and type of filter is in your cooling system’s manual, which may be available online. However, you may need to replace the AC filter more often than recommended, depending upon how much you use the AC.
  • Fan motor malfunction, which again leads to low airflow. Motor problems may be prevented, or discovered before it breaks down completely if you schedule annual cooling system maintenance from your reliable local AC technician.
  • Blower fan belt worn, slipping or broken, leading, again, to low airflow. This wear and tear issue can be easily remedied during an AC maintenance visit. Your HVAC contractor will inspect the entire system during the routine visit, and recommend a replacement for any worn parts. The tech will also inspect and clean the evaporator coil, compressor, and other components, lubricate the system, check for leakage, recharge the refrigerant (if needed), check safety controls and more.
  • Collapsed air duct, causing low airflow and coil freeze. Other duct system problems may be contributing, such as not enough air return ducts.
  • Dirty evaporator coil may interfere with proper heat transfer or absorption, causing a frozen coil.
  • Faulty thermostat, which can keep your AC running instead of periodically cycling off. Constant running can freeze up the coil.
  • Clogged condensate drain or line. This inhibits disposal of excess moisture. Water that should drain out stays in the system, can freeze and block the refrigerant coil.
  • Expansion valve problem, stuck open or closed.
  • Refrigerant leak, which causes a low refrigerant level, can also allow the coil to freeze up. (When refrigerant is low, there’s not enough to absorb/transfer heat properly.)
  • And more. Your friendly, local HVAC team is ready to help with expert air conditioner repair in Chalmette and surrounding areas.

What to Do About Frozen Cooling Coils in Chalmette

Now that we’ve discussed what happens inside your AC to make the coils freeze, and learned the main causes of frozen coils, we’ll talk about a DIY solution for your air conditioning freeze-up. Here are the steps to diagnose and unfreeze your air conditioning system’s frozen evaporator coil:

Preventing Further Air Conditioner Damage

    • Although the circuit breaker may have tripped if the AC has overheated due to stress, go ahead and turn the cooling system off (at the thermostat).
    • Place a bucket under the AC condensate pan (which is below the air handler) to catch any overflow of water as the frozen AC coil melts.
    • Then, set the AC system on “fan”, which can start to melt the icy coil with warm airflow.

Troubleshooting Your AC Coil Freeze

  • Look for a dirty, clogged air filter and replace if necessary. When the coil has melted, turn the air conditioning system on once again and watch for re-icing. If it begins to ice up again, shut off the AC and call in an HVAC pro.
  • Check for airflow while the system is on “fan.” If airflow is limited or non-existent, the issue may be the blower (dirty and/or faulty belt). Otherwise, you may need a new fan motor. It’s time to call your local HVAC contractor for precise diagnosis and AC repair in Chalmette.

The Solution to All Your AC Problems

Your air conditioner coil is generally sealed, and proper refrigerant handling/disposal and recharging must be done by a professional for safety–so you can’t go further with DIY methods. Contact a local HVAC contractors for assistance on your AC unit.