What Causes an Air Conditioner to Freeze Up?
Low refrigerant is often the primary reason for an air conditioner freezing up.
Homeowners want their air conditioners to keep their space cool and comfortable when the temperatures outside rise. However, an air conditioner needs the correct pressure, airflow, and temperature balance to cool down those interior areas. Changing this balance might damage the system, often leading to a frozen air conditioner. Here are some of the top reasons an air conditioner might freeze up and how to prevent them.
Low refrigerant
Low refrigerant is often the primary reason for an air conditioner freezing up. Leaks in the unit or an undercharged coolant during installation can trigger problems. Low refrigerant levels may cause the evaporator to cool the coils excessively. Addressing this problem might seem like a quick DIY task, but hiring a professional is better.
Clogged air filters
Blocked and dirty air filters can be detrimental to homeowners' cooling systems. Routine maintenance can avoid many such issues. A grimy filter can reduce airflow to the system, adding strain on the compressor and other AC components—decreased airflow results in less air delivered to the evaporator coils, reducing component cooling. Ensuring a steady flow of humid and hot air can prevent the coils from freezing.
Homeowners can resolve this problem by replacing the filter regularly.
Closed vents
While closing vents and registers may seem like a money-saving approach to energy costs, it could backfire. Over-closure of vents in a home disrupts the air balance, causing the air conditioner to freeze. Ensure that no more than a quarter of vents are closed at any given time to prevent a frozen air conditioner.
Malfunctioning fan
The fan is a critical component of the air conditioner. It must blow at a speed adequate to maintain sufficient airflow over the evaporator coils. A trained technician should resolve any fan issues. Although fan speeds can be increased manually in a unit, investigating potential underlying issues affecting the fan's power is recommended.
Broken thermostat
A malfunctioning thermostat can lead to a frozen air conditioner. An air conditioner may run even when the home is adequately cool. Although your indoor air temperature may be at the desired level, a faulty thermostat might misread it, causing the air conditioner to freeze up. Such a situation can lead to energy and financial waste, requiring a professional to examine the thermostat for potential replacement.
Drainage problems
Drainage issues are another factor resulting in a frozen air conditioner. In hot and humid climates, the cooling system must work extra hard to eliminate heat and moisture from the air. In such climates, the water vapor turns into condensation in the unit. Usually, this water trickles out through the floor drain. When something obstructs the drainage pipes, the water might freeze within the evaporator coils. Ice can block the drain, leading to further complications for the unit. Clearing the drainage pipe during the hottest summer days is advisable. If the system operates properly, water will regularly exit through the floor drain.
Improper placement
Finally, improper alignment of a window unit can cause it to freeze. The unit should be slightly tilted, with the indoor part higher than the outdoor one. Incorrect positioning prevents water from exiting the drainage hole, causing it to accumulate in the unit and freeze. Adjusting the unit alignment can resolve freezing issues.
How to fix a freezing air conditioner
If an air conditioner freezes, specific steps can help prevent damage. Switch off the system to avoid any harm to the compressor. Then, check the drain for blockages. If a wet/dry shop vacuum is available, it can be handy to suction out the water from the ductwork.
For accelerating the defrosting process, a blow dryer on the evaporator coils can help melt the ice. Activating the air conditioner fan can also facilitate rapid ice dissolution. Switch on the air conditioner after melting the ice and clearing any blocked drainage pans. Nevertheless, it's advisable to call a professional technician to investigate the problem. The recurring freezing of the air conditioner suggests a deeper problem.
Keep the air conditioner in top shape
A frozen air conditioner is a serious issue. Regular checks on refrigerant levels, air filter changes, and keeping air vents open with the correct fan speed in the unit can help avoid such problems. Ensure that the drainage pipes are clear to prevent condensation issues. It is always best to have regular, professional HVAC system maintenance to avoid these issues altogether.
CMB Air is a residential heating and cooling installation, service, and repair company with 15+ years of experience serving Tampa and surrounding areas. If you need a new air conditioner, repair, maintenance or some other service, we can help! Call (813) 447-1443 today!
