How Can I Fix AC System Freezing Up On The First Try

Is your air conditioner freezing outside your home? Especially in the middle of summer, it can be surprising to see a piece of ice on your outdoor air conditioner. But sometimes you can't even see the ice outside the device.

You might think that an air conditioner can't freeze in the summer, but this is a common occurrence on the hottest days of the year.

If you're worried about a frozen air conditioner, read on to find out the causes, how to fix a frozen air conditioner, and how to prevent your air conditioner from freezing so it doesn't happen again.

Why Does My Central Air Keep Freezing Up?

To understand how an air conditioner can freeze, you must first understand the basics of how central air conditioning systems work. And it all starts with your evaporator coils.

This important air conditioning component is filled with extremely cold refrigerants. When the coils are activated, hot air must flow through the refrigerant. This will cool your air and keep the coils warm enough so they don't freeze. The indoor coil extracts heat from the indoor air and then uses refrigerant to transfer it to the outdoor coil, which pushes the heat outside. The indoor coil extracts heat from the indoor air and then transfers it to the outdoor coil using the refrigerant. The outer coil pushes the heat outwards. That's why if you ever place your hand on your outdoor unit's running fan, the air will be noticeably warm.

However, if something breaks in the air conditioning system, the entire system is disrupted. When something prevents hot air from flowing over the coils, the evaporator coil allows the refrigerant to cool too much, causing it to drop below freezing and freeze. Or if the refrigerant pressure in the coils is too low, your system's coils can get too cold and freeze quickly. And that can lead to a freezing cold air conditioner.

What to Do When Your Air Conditioner Freezes Up

If you think your outdoor air conditioner is frozen, you can follow a few simple steps to fix the frozen air conditioner problem and get it back up and running.

Step 1: Thaw

Avoid using the air conditioner if the evaporator coils are frozen. Operating the air conditioner with frozen coils puts strain on the air conditioning compressor. Access your electrical circuit breaker and turn off the power to your AC unit. This prevents the system from freezing even more and the ice from melting. The air conditioning compressor is the most expensive component of your air conditioning system. The stress could damage this incredibly valuable part and expose you to a costly air conditioning repair call.

Even if it's very hot outside, it can take a whole day for the ice to completely melt. Do not try to break the ice with a heavy object or sharp tool. This damages components so badly that you have to replace multiple parts, which can add up financially, or worse, force you to replace the system entirely.

Step 2: Dry

Once the ice has completely melted, you will need to dry the evaporator coils. You can use paper towels or let the pieces dry in the sun if they are in direct sunlight. Restore power to your system and turn on the fan. Go in and set your thermostat to run just the fan or the fan, depending on which thermostat model you have. This circulates air around and through the coils to dry them quickly. Once the coils are completely dry, your system should function normally again.

Now that you know what to do if your air conditioner ever freezes, let's talk about how to prevent it.

How to Prevent a Frozen Air Conditioning System

It is important to recognize that this is preventable. Follow these steps to prevent your HVAC system from freezing, whether you have a York, Carrier, or Lennox unit.

Change Your Air Filter

The main cause of a frozen HVAC system is a dirty air filter. The air filter cleans the air circulating in your home. When your air conditioner runs all summer, the filter traps dirt, pollen, dust and other allergens. This can restrict airflow and lead to frozen HVAC coils. We generally recommend checking your filter monthly. Change it if necessary. For most people, this happens every three months. Filter changes vary depending on factors such as:

  • The type of filter you have
  • If you have children or pets in the home
  • If you live in a high-pollen count area
  • Whether a smoker lives in the home
  • If someone with asthma, allergies, COPD or congestive heart conditions lives in the home

Schedule Regular Maintenance

It's simply good practice to do an annual air conditioning maintenance visit. The professional HVAC technicians at Bannister Plumbing & Air will ensure that all of the following items are checked and cleared to keep your system running smoothly this coming summer:

  • Inspect coolant levels and pressure to ensure your system runs at peak efficiency
  • Calibrate thermostats and check proper cycle and temperature to improve comfort and control
  • Inspect and tighten wiring, contacts, capacitors and relays to avoid expensive repairs
  • Ensure the evaporator coil is clean
  • Ensure the condensate drain is clear
  • Inspect and clean the condenser
  • Inspect the outdoor disconnect switch
  • Inspect the condenser fan motor and blades; lubricate if needed
  • Check compressor amps at startup
  • Carry out additional safety and efficiency checks

It is also advisable to avoid handling coolant chemicals as they can be toxic. Leave it to our technicians and avoid dealing with them if possible.

Have an HVAC Airflow Inspection

Restricted airflow can prevent the coils from cooling properly and lead to a frozen air conditioner. Similar to a clogged filter, blocked air returns and dampers prevent proper airflow to and from the system. This forces your system to work harder without the ability to exhaust the cooled or heated air.

Another best practice is to walk through your home and check that the vents and registers inside are clear of obstructions. If you're concerned that there's not enough airflow through your vents, your ducts could be the cause. In some cases, the ducts are installed properly but are not the right size for your home or its capacity. Or there is a leak in a duct or a section of duct has collapsed somewhere in your walls.

Clean Evaporator Coils

Condensate lines drain excess moisture from your HVAC system. If there is a blockage in the pipe, water gets stuck and excess water freezes. And the frozen water in your pipes could also lead to frozen HVAC heat exchangers. This causes your system to struggle or not work at all.

Check the Forecast

Are temperatures expected to drop at night in summer? A good rule to remember is that you should turn off your air conditioning when the outside temperature drops. Running your outdoor air conditioner on cooler nights can cause icing. A special ambient temperature control installed can help prevent your device from operating in cooler weather.

A Frozen AC is Avoidable

While it can be frustrating for a homeowner to find a frozen air conditioner, the problems that lead to it are preventable. It is important not to neglect regular maintenance and optimization of your air conditioning system every year. Hiring a professional HVAC service team like Bannister Plumbing & Air or taking advantage of maintenance service plans can help keep your system running smoothly year-round and save you money.

Find our nearest location to schedule service online or by phone. We are available for any emergency air conditioning service, including a frozen air conditioner.