Five Causes of Frozen AC Coils and How To Fix Them

Although frozen AC coils are a fairly common problem, you shouldn’t ignore them or expect the issue to be resolved on its own. Letting the coils remain encased in ice can destroy other HVAC components, leading to bigger, more expensive problems. So, can you remedy the icy coils by yourself, or do you need professional assistance? 

A1 Mechanical’s HVAC contractors in Dayton, OH, have seen their fair share of coil concerns. They shared what may cause them and whether you can fix them below. Read on to find out if you need our help. 

How Can You Tell If You Have Frozen AC Coils?

Coil cleanings are typically included in the average air conditioner maintenance checklist. Your technician removes, wipes, and perhaps rinses the coils before replacing them. This task prevents many of the issues we’ll explore below. 

However, if you can’t remember the last time you scheduled HVAC maintenance in Dayton, Ohio, you might have a mess on your hands in the future. Frozen coils can manifest in the following ways:

• Your air conditioner runs for ages, but the air never feels any cooler. 
• You’ve noticed tiny leaks trickling from vents, soaking ceiling material, or creeping from behind walls.
• The air feels thick and dense with excess moisture.
• You discover puddles of water beneath the outdoor unit.

Turn off your HVAC system and assess the problem. Otherwise, you might pay for expensive issues like compressor troubles or water damage mitigation. 

Causes and Remedies for Frozen Coils

When we talk about frozen AC coils, we could mean either evaporator or condenser coils. Evaporator coils remove heat from your indoor environment before passing it on to the refrigerant. The heat escapes outdoors via the condenser coils, which condense the refrigerant back to a liquid form. 

Both coil sets can freeze, forcing your cooling system to run without producing heat, wasting energy, and overworking other HVAC components. Let’s explore the causes and potential fixes below. 

#1 Restricted Return Vent

The return vent sucks air from inside your building back into the air handler. The handler then reconditions the air to your preferred temperature before recirculating it. If the return register cannot draw in air without struggling, it may cause the evaporator coil to freeze.

The most common reasons for this restricted airflow are a filthy HVAC filter or a blocked register. First, locate the return register and check for furniture, laundry piles, or boxes blocking it. If you don’t see anything, open the register and replace the filter. 

#2 Low Refrigerant Levels

Low refrigerant levels can cause the condenser and evaporator coils to freeze. The refrigerant absorbs and moves heat out of your building. Both sets of coils play a role in releasing the heat. 

Insufficient refrigerant means lower refrigerant temperatures, which can cause ice to form on the coils. Listen for hissing near your indoor and outdoor equipment. If you hear these sounds, contact an emergency HVAC technician to mend the refrigerant lines and replenish the supply. 

#3 Thermostat Malfunctions 

Your thermostat may also be the culprit behind your frozen AC coils. Are the evaporator coils frozen solid each morning? If so, they got icy overnight, and you’ll find a trickling stream starting around the outdoor unit as they thaw. 

This problem goes far beyond choosing the wrong thermostat settings. It means your device isn’t communicating well with the air handler. The thermostat might detect a higher temperature than the room’s actual reading, forcing the system to work too hard when it should take a break at night. 

#4 Filthy Evaporator Coils

Dust gradually coats the surface of your evaporator coil, keeping air from flowing freely and warming the condenser coils. This is another type of airflow restriction that occurs within HVAC machinery. As a result, the refrigerant can’t take in enough warmth to heat the condenser coils.

The moisture on the coils hardens into crystalline ice, further stressing and overworking the system as it fights to reach your temperature settings. You can avoid dust-caked evaporator coils with an annual maintenance visit from your HVAC company in Dayton, Ohio. In the meantime, you’ll need an impromptu coil cleaning service to mitigate the problem. 

#5 Clogged Condensate Drain

Air conditioners come with miniature plumbing systems designed to handle condensation from the heating and cooling process. It’s called the condensate drain line, and it drains the water that trickles from components handling heat from the refrigerant. Sometimes, the tiny drainage system develops a clog in the line. 

Water collects in the drainage pan until it overflows. The excess water backs up and insulates the evaporator coil, preventing it from absorbing heat. As a result, the coil forms a thick layer of ice. Shut off the air conditioner and contact an HVAC technician to unclog the condensate drain line. It’s a fairly quick fix that doesn’t take long to resolve. 

Annual Tune-Ups Prevent Frozen Coils

You might have noticed a running theme in the reasons for icy coils explored above. Consistent air conditioner maintenance on your and your technician’s part prevents most of these issues by:

• Refreshing the HVAC filter
• Keep vent openings free and clear
• Checking and refilling the refrigerant
• Calibrating and adjusting the thermostat
• Cleaning both coil sets and other vulnerable components
• Clearing the condensate drain pan and attached line

Your technician will also adjust and lubricate moving parts while checking electricity usage. Our team recommends twice-annual HVAC maintenance visits. Schedule one in the spring to prepare your air conditioner for problem-free service. The autumn visit will address your heating system for a cozy, peaceful winter. 

Schedule Your Air Conditioner Maintenance Service With A1 Mechanical in Dayton, Ohio

Don’t wait to address frozen AC coils! They can manifest as an AC leaking water or not sufficiently cooling the air. If you can’t solve the issue at home, call A1 Mechanical at 937-865-2325 for air conditioner maintenance or repair services in Dayton, Ohio. Let’s get crisp, cool air moving through your home or business again.