Why Outdoor HVAC Units Ice Over and How to Address It

An outdoor HVAC unit is left exposed to all sorts of elements, such as rain, dirt, debris, leaves, insects, critters, and more. One of the more challenging obstacles to any outdoor system is ice.

Below are the four most common reasons why an outdoor unit might accumulate ice and how to address the problem. 

Why Ice Accumulates on HVAC Units and What to Do About It

Reason #1: 

A dirty air filter. A clogged or dirty filter can restrict air movement, leading to the evaporator coil becoming so cold that moisture from the air freezes on the line.

The fix: Replace your air filter. Then, turn your system off, but turn the fan to “on” so the evaporator coil can defrost. It may take a few hours, but you’ll know it’s been fully defrosted when the air coming out of the vents has returned to normal. 

Reason #2:

A leak in the copper line caused by corrosion has led to a drop in the refrigerant level. This in turn drops the temperature of the evaporator coil so low it freezes over.

The fix: Call on a professional to locate the leak and discuss some options for how to fix it. 

Reason #3:

A faulty blower not generating enough warm air to stop the evaporator coil from freezing up.

The fix: Listen for the blower. If it’s not running, call a professional to investigate further. 

Reason #4:

Debris has accumulated on the evaporator coil and is impeding the flow of warm air needed to prevent ice formation on the coil.

The fix: Call on a professional to clean the coil. 

Keep Ice Away With Preventive Maintenance

An effective way of keeping ice off your HVAC system is to have preventive maintenance performed on a regular basis. Every spring and fall we offer our 15-point inspection for residents in the Wilmington, NC, area to help keep units clear of debris, leaks, and faulty parts that can cause ice to form. Schedule an appointment online or contact us at (910) 791-1988 to learn more about our preventive HVAC maintenance.