How to Fix a Frozen AC Unit | A Complete Guide

frozen ac unit

The air conditioner in your home is an important part of your indoor air quality and comfort. An efficient and properly working air conditioning system makes the difference between a comfortable and cool summer from a miserably hot one. Therefore, a frozen AC unit is something you don’t want to deal with during these hot days.  If you’re dealing with a problem with your AC right now, routine check-up, or tune-up, contact Joseph The Handyman for a free quote, or directly text or call this number +1 (916) 269-5293.

But before you do, let me help you with this article first. 

frozen surface

How to Know if Air Conditioner is Freezing?

It’s ironic to say your AC is freezing on a warm summer day. Regardless, it’s not a normal condition and it’s a concern that should be addressed immediately.

The first warning or sign that your air conditioner might be building up ice is when you feel that it’s no longer reaching the thermostat setting you desire. If you feel that your ac system is not cooling efficiently, first, try to feel the air that’s coming out of one of the supply registers. Feeling warm air instead of cool is not a good sign. Then, get the manual or manufacturer’s diagram and open the access panel to the evaporator. Seeing the coils or any equipment inside engulfed in ice is visual proof that your refrigerant has dropped below freezing point resulting in a frozen compressor on ac unit.  

frozen evaporator coil

What are the Common Causes of a Frozen AC Unit?

Though the entire process may appear complicated, the causes of a frozen ac unit inside are pretty basic. 

1. Insufficient or restricted airflow

When your air conditioning system has an obstructed airflow, it’s gonna have a hard time pulling the heat from your house into the unit. As a result, condensation forms on the coils which makes it into ice. Basically, insufficient airflow will drop the temperature of the evaporator coil to below freezing. Likewise, humidity in the air will also gather on the coil, turns into ice build-up, and reduces the system’s cooling efficiency.

One of the causes of restricted airflow is a dirty evaporator coil. Further, it’s a contributing factor to other more serious problems with your AC such as Dirty Sock Syndrome. Other causes that impede airflow are obstructed ducts, dirty air filters, and damaged blower motors.

2. Low refrigerant level

Refrigerant is the liquid agents that make air conditioning systems work. That said, low-level refrigerant creates low pressure which means low temperature, eventually, causing the evaporator coils to freeze. This is known as the Joule-Thompson effect. Joule-Thompson Effect is the basic foundation that made air conditioning unit possible today. 

In other words, low-level refrigerant or refrigerant leaks can cause pressure to drop in the AC evaporator coil which allows moisture in the air to freeze up the coil.

3. Mechanical failures

Air conditioning units have a lot of mechanical components such as compressors, fans, and expansion devices. If one of these components is malfunctioning, it can mess up the pressure and temperature of the unit and eventually, freeze up your air conditioner.

4. Outdoor temperature

Most outdoor AC units do not perform well in temperatures below 15 degrees C. Freeze-up can occur if the temperatures at night are too low. In normal operation, unconditioned, and warm air passes over the evaporator coils. In fact, the warmth in your home’s air prevents ice formation. Therefore, lack of warm air across the coils could cause freeze up.

The Good News?

It’s a problem you can try to solve before anything gets worse. If the cause is a dirty filter, you can just change or clean it. You know now the early signs and causes of an AC unit with frozen pipe inside, giving you a better chance of detecting any problem early on. The key is to not let the problem grow. Address the issue, fix it, take actions to avoid having the same issues over again

frozen ac unit

How to Fix a Frozen AC Unit?

As I’ve said, when detected early, fixing a frozen AC unit should be simple. Though fixing a frozen air conditioner may require the expertise of a certified HVAC technician, there are things you can try to do yourself first.

Follow the steps below to know what actions to take.

1. Thaw your air conditioner

If you’re certain that your evaporator coils are frozen, do every effort not to use your unit. In fact, using your AC while the coils are frozen puts strain on the AC compressor. Moreover, the compressor is the most expensive part of your air conditioning unit and you wouldn’t want to deal with unplanned expenses.

If your air conditioning unit is frozen, the first thing to do would be to thaw it out and let the coils dry. Simply, turn off your unit from the breaker and let the ice thaw.  Alternatively, you can also switch the thermostat off and the fan on. This action will help minimize further damage and let you see better what’s going on inside your unit. Take note, it could take you a whole day to completely thaw the ice so it’s best to plan when to do this process. 

More importantly, don’t listen to any advice saying you should break the ice by force or by a sharp object. This can cause more problems than you already have.

2. Find the underlying cause

Obstructed airflow is mainly caused by the build-up of the debris your filter has caught. As I said earlier, insufficient airflow can freeze your AC. If your air filters are dirty, clean them off. Better yet, replace them if you have spare but haven’t done so in a while. Generally, air filters should be replaced once every 2 – 3 months depending on usage.

However, if your air filters are not dirty, call professional service right away. Though a dirty air filter is not the only reason for a frozen AC unit, it’s one of the few problems that you can solve yourself. Contact me for HVAC services in Sacramento.

Dirty evaporator coils can also impede airflow. Refer to your unit’s user manual to know how to access your panels and coils. Then, to clean the coils, turn off your AC unit and use either a soft brush or compressed air to remove the dirt. Additionally, check if any of the supply registers in your home is closed as blocked registers also cause problems.

Low levels of refrigerant do not only reduce the performance of your air conditioning but also, indicate a leak. It is crucial to check for leaks not only to determine the cause of your frozen AC but also, to avoid harmful effects from prolonged exposure to freon. Some refrigerant leaks are easy to see, however, slow leaks are harder to notice. One option is to do a dye leak test. First, mix a small amount of fluorescent dye with the refrigerant. Then, observe. You should notice brighter colors on the ground if it’s really leaking. If so, contact a professional to fix the leakage.

3. Restart your AC unit

After taking the steps above, try to see if you’re unit is properly cooling again. If you turned the breaker off, restore the power and set the thermostat to cool. After a few minutes, cool air should be blowing from the vents. If otherwise, or if it still takes a long time to reach the thermostat setting, go to step 4.

4. Seek professional help

If you’re AC is still blowing warm air, it will probably freeze again if you use it. This time, consult a professional HVAC technician to correct your issue. Not only will a professional technician be able to determine the cause, but also he can do exactly what needs to be done to fix your unit. Furthermore, an HVAC professional can give you an assessment of whether repair or renewal is a more cost-effective solution. 

ice cubes in fire

In conclusion, staying frosty on hot summer days is hard when your AC unit is doing the same. Frozen coils stop your air conditioning system from doing its purpose, thus, maintenance is crucial to prevent this from happening. Though there are things you can do to fix this problem, a preventive and proactive mindset goes a long way in saving you money, energy bills, and headache with your HVAC system.

Contact me for professional assistance when your air conditioning freezes up. Or, directly text or call this number +1 (916) 269-5293 to schedule an appointment.

How to Fix a Frozen AC Unit | A Complete Guide
Article Name
How to Fix a Frozen AC Unit | A Complete Guide
This article is about frozen ac unit, how to detect if your unit is freezing, and things you can do to fix it. It is a complete guide for you to make an informed action and decision.
Joseph B
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Joseph The Handyman
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