Short- And Long-Term Solutions For A Frozen AC Coil
Your air conditioner's evaporator coils will freeze when the coil begins to reduce the surrounding air temperature below freezing. Air conditioners dehumidify the air by causing moisture to condense onto the coil, so the coil temperature must always remain above the freezing point of water. If the coil is too cold, ice will form a layer of insulation that will stop the coil from absorbing any additional heat.
An icy coil will reduce system efficiency and often result in damp, clammy air from your vents. As the ice builds up, the system will eventually stop operating. If your system is freezing up, you might notice the air from your vents becoming gradually colder until your AC shuts down prematurely. This guide will discuss short- and long-term options to correct this situation and protect your AC equipment.
Short-Term: Prevent Further Damage
A frozen evaporator coil is more than just a nuisance. All air conditioning systems operate within relatively tight tolerances and rely on refrigerants to change phases between a vapor and a liquid. A frozen coil will prevent your system's refrigerant from acquiring heat, potentially preventing the refrigerant from vaporizing. Liquid refrigerant returning to the compressor can cause serious damage.
If you think your system might be freezing up, stop using it immediately. Since low airflow can cause your evaporator to freeze, you can try checking your air filter. If the filter seems particularly dirty, replace it and give the system time to thaw before using it again. You may need to wait a whole day for the coil to thaw out fully. Also, check for obstructions, such as furniture near return vents.
Do not use your system if it continues to freeze after replacing the filter and ensuring adequate airflow through all return vents. You most likely have a refrigerant pressure problem at the evaporator coil in these cases. While your system does include safety features to shut down and prevent damage, the safer option is to avoid running the system until you resolve the underlying problem.
Long-Term: Diagnose and Fix the Root Cause
Aside from dirty air filters, the most common causes of frozen evaporator coils are refrigerant leaks and restrictions. Unfortunately, checking or replacing refrigerant in an air conditioning system isn't as easy as topping up on oil in your car. In addition to requiring specialized equipment, understanding your system's pressure readings requires expert interpretation.
More importantly, the symptoms of a leak and a restriction can be very similar. Even if you think your system is losing refrigerant, the underlying problem may be a restriction in a component such as the thermostatic expansion valve (TXV) or another metering device. A professional HVAC technician can investigate these problems so you don't waste money replacing the wrong part.
Contact an AC services provider to learn more.
