Why is My AC Freezing up? How to Fix [With Pictures]

Figure 1: Outside air conditioner unit frozen.

Every summer people will think of using air conditioners to help lower the temperature. This will allow them to live better and more comfortably. However, many people find that after using the air conditioner for a long time, the AC frozen phenomenon shows up and causes the air conditioner not to work properly.

So what should you do when your AC unit frozen?

1. What to Do When Your AC Unit Freezes Up?

Quick Fix for AC Freezing up:

Step 1: To melt the ice, you need to switch the air conditioner from cool mode to off. Then turn on the fan, which will help blow warm air to the frozen AC coils, speeding up the entire thawing process. You can even use a hair dryer if you want to quickly thaw out the air conditioner.

Step 2: If you notice water dripping from the outside of the drain pan, into the pipes and other parts, use a wet/dry vacuum cleaner to clean it up. While indoor AC units leak water for many reasons, evaporator coil freezing is one of the main causes.

Step 3: After the ice thaws, you'll need to let the evaporator coil dry. Remove the cover of the indoor unit, then turn on the air conditioner and let the AC dry.

Step 4: Find out why and fix it. There are several reasons for the AC freezing up as the following.

2. What Causes the AC to Freeze and How to Fix It?

There are 8 causes for AC freezing up:
●Dirty Evaporator
●Insufficient Refrigerant
●Excessive Refrigerant
●A/C Compressor Failure
●The Air Volume of the Indoor Unit is Small
●Thermostat Failure
●Temperature Setting is Too Low
●Pipe Blockage

2.1 Dirty Evaporator

If the air conditioner has been used for a long time, it may cause the surface of the evaporator to be dirty. If the evaporator is too dirty, it may cause the evaporator to freeze due to too low temperature.

The best solution is to clean the evaporator.

Figure 2: Dirty air conditioner evaporator.

2.2 Insufficient Refrigerant

Due to wrong installation or long-term use of the air conditioner, refrigerant leakage may occur. After the refrigerant in the refrigeration system is reduced, the evaporation pressure is too low, causing the evaporator to freeze, and the freezing position is generally in the front part of the evaporator.

The best solution is to deal with the leaking part and add enough refrigerant into the system.

2.3 Excessive Refrigerant

If there is too much refrigerant in the air conditioner, it will also cause the low pressure pipe of the air conditioner to freeze. Just let off the excess refrigerant.

2.4 A/C Compressor Failure

If the AC compressor is used for too long, it may cause less efficiency, reduced power or damage. This will cause the pressure of the compressor to be relatively small, which may eventually cause the system to freeze due to too low pressure.

At this time, you can add refrigerant to the compressor to see if the problem can be solved. If it cannot, you need to replace the AC compressor.

Figure 3: Air conditioner compressor repair.

2.5 The Air Volume of the Indoor Unit is Small

After the air conditioner has been used for a period of time, a lot of dirt will stick to its fan blades, which will eventually affect the air supply and cause the evaporator to freeze. The way to deal with this situation is to clean the dirt on the fan.

2.6 Thermostat Failure

A malfunctioning thermostat is also the reason for the air conditioner freezing up. Generally speaking, just replace the thermostat.

2.7 Temperature Setting is Too Low

Some users set the temperature of the air conditioner too low, and the cooling capacity of the air conditioner cannot keep up, causing the AC to work for a long time. In some rooms, the temperature drops very low, which can also cause the evaporator to freeze due to the low temperature.

Usually under this situation, the freezing starts to form from the lower part of the evaporator. As long as the temperature is set higher, the fault can be eliminated.

2.8 Pipe Blockage

Internal blockages in the pipes can also cause the AC unit freezing up. The temperature of the refrigerant in the thick pipe is relatively low, and a layer of frost will appear on the surface of the pipe.

If the temperature of the tube continues to be low, it will cause the tube to freeze. It is necessary to clean the inside of the tube by injecting nitrogen into the pipe.

If the thick pipe of the air conditioner is flattened, maybe caused by improper installation or deformation under abnormal temperature, the refrigerant inside the pipe cannot continue to circulate, and the pipe needs to be straightened. If the deformation is serious and the pipe cannot become normal, it is necessary to replace the old pipe to solve the problem.

Figure 4: Air conditioner pipe is frozen.

3. Hazards of AC Frozen

The following information highlights some of the problems that severe frost and icing can cause with your air conditioning system.

3.1 Poor Cooling Effect

Normally, as room air flows over the evaporator coil, the coil helps cool the air by absorbing latent heat from the air flow. Outside, the condenser coil relies on airflow to release heat into the atmosphere.

When the evaporator of the indoor unit is blocked by ice and cannot blow out air, excessive frost and ice buildup can prevent air from flowing through the coil, resulting in the coil not functioning properly. Without a steady source of airflow, your air conditioner won't be able to cool your home effectively.
In this case, you may feel the airflow from the air conditioning vents weaker than usual, with poor cooling performance. If this problem is not addressed, more serious failures may occur.

3.2 Increasing Energy Consumption

Another consequence of excessive frost and icing is a significant increase in energy consumption for air conditioning. At this time, while your air conditioner is trying to keep your home cool and comfortable, it uses more energy than usual because its components are working harder than usual. All that constant hard work will result in your monthly energy bill increasing.

3.3 Water Leakage

Severe frost and icing can lead to another unexpected problem—water leaks. Your air conditioner has a unique drip pan that collects water as it condenses from the warm air and then drains it out of the system. And a lot of melting ice can easily flood your drip pan, and the water spills from the edge of the pan onto the ground below.

Figure 5: Drip pan of air conditioner.

4. How Do I Keep My Air Conditioner from Freezing up?

Replenish the air-conditioning refrigerant in a timely manner, and the supply should be appropriate, neither too much nor too little, so that the possibility of AC freezing up can be greatly reduced.

Pay attention to the maintenance of the air conditioner in daily life, and decontaminate and clean the evaporator of the air conditioner from time to time. Keeping the evaporator clean can often effectively avoid the air conditioner freezing up.

5. FAQs

5.1 What to Do When Your AC Unit Freezes up inside?

Keep the refrigerant in the system at the proper level
Freezing in the air conditioner inside may be due to lack of refrigerant, resulting in low pressure of the air conditioner. At this time, the air conditioner will freeze, and the user needs to add refrigerant in time.

It may also be that the refrigerant in the air conditioner exceeds the set amount, resulting in freezing, and the user needs to release some refrigerant in time.

Although the refrigerant can be bought on the market, if the user has no operating experience, it is generally better to find a professional to add it for you. They have fast speed and will not add too much refrigerant into your system.

Clean the air conditioner evaporator
It may be that the evaporator of the air conditioner is blocked and the heat exchange efficiency is reduced, resulting in the freezing of the air conditioner due to the low temperature. When users encounter such problems, they need to ask professionals to clean the air conditioner.

Check whether the compressor has failure
It may be that the power of the air conditioner compressor is reduced or the compressor is broken, so that the AC compressor cannot operate normally, and the air conditioner is prone to freezing. The user needs to ask a professional to check the cause of the compressor failure.

Figure 6: Test the compressor with a pressure gauge.

5.2 What to Do When Outside Air Conditioner Unit Frozen?

The freezing phenomenon of the outdoor unit of the air conditioner generally occurs in winter. How to deal with the icing of the outdoor unit of the air conditioner include the following four ways:

●Turn off the air conditioner, boil a pot of water and pour it on the outside air conditioner unit to melt the ice, and then use the air conditioner after drying;
●Turn on the defrosting function on the control panel;
●Turn the air conditioner into cooling mode. If the temperature is not high enough, you can put the temperature probe into the hot water cup;
●Wait for the temperature to rise so that the ice will melt naturally.

5.3 Will Frozen AC Fix Itself?

The ice on the air conditioner can melt on its own, but it takes a long time. If the outdoor temperature is always low, the ice on the air conditioner will not melt by itself.

If the AC keeps freezing seriously, it is necessary to find out the cause of the freezing and carry out corresponding troubleshooting.

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