Common Reasons Your A/C Freezes Up

Day after day, year after year, you depend on your air conditioner for indoor comfort, but when your A/C freezes up (which can happen even in the summertime), it can malfunction. Coolant cannot absorb heat from the indoor air when something is wrong that requires an air conditioning repair technician to address.

If frost forms on refrigerant lines or ice coats interior components, these are some of the most common reasons:

Blocked Airflow

When it’s running normally, the A/C draws indoor air and forces it over the evaporator coil, where the refrigerant absorbs heat. It’s important for air to continuously flow over the coil. Otherwise, condensation will form and the coil can freeze. If you see ice on the evaporator coil or excessive condensation, call a technician to determine why your A/C is freezing up.

Dirty Air Filters

Dirt can clog up filters more quickly in dusty air. If it’s been a few months since you changed the filter, it’s time to check it, whether you notice air conditioning issues or not. When the filter blocks air passing through the A/C system, not enough heat is transferred from your home to the refrigerant, so the coolant stays colder and causes condensation (and eventually ice) to form on the coils and outdoor unit.

Low/Leaking Refrigerant

Refrigerant enables the system to achieve the desired temperature you set on the thermostat. There must be enough of it to expand to the required amount. If levels are low or refrigerant is leaking, the coil may freeze over and the compressor can overheat and fair. If the leak is severe, or your system still uses R-22 refrigerant (which is being phased out in 2020), consider replacing the A/C system.

Mechanical Problems

Air conditioners have many moving parts. A blower fan can jam up or break and refrigerant lines can corrode or leak. Various other components can break, get stuck, or clog up. An air conditioning company can inspect the system, if it’s freezing up, to find the exact cause and either fix it or provide a reliable replacement.

Dirty Coils

Just as dirt in the filter can cause trouble, so can dirt on the A/C coils. It can impede normal heat transfer, causing the colder refrigerant to condense moisture that freezes up. If you can access the coils, clean them or call a technician if you’re uncertain how to do it properly.

Faulty Thermostats

If the thermostat isn’t turning off at the right temperature, the air around the cooling coil can get too cold. This isn’t uncommon in older systems. The air conditioner can freeze if it continues to run when the temperature is too low, especially when it’s operating in cold weather.

Call Us if Your Air Conditioning Unit Is Freezing Up

At Christianson Air Conditioning and Plumbing, we can fix your frozen A/C and provide air conditioning maintenance, repair, installation and replacement services that are reliable. We have served Austin and San Antonio, Texas since 1950. Homeowners and builders depend on us for professional air conditioning repair. Call 512-246-5400 for prompt and professional service.

Tags: Causes of AC freeze-up, Frozen air conditioner, Frozen coils