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AC Freezing Up
in Boynton Beach, FL
It seems strange that an AC unit in Boynton Beach could freeze in 90-degree weather, but it happens regularly. The evaporator coil inside the air handler operates at very low temperatures, and when airflow across it drops, the coil gets so cold that moisture in the air turns to ice. That ice layer builds up and eventually blocks all airflow entirely. When the ice melts, it can overwhelm the drain pan and cause water damage to ceilings and floors below the unit.
Quick Answer
Ice on your AC unit means the evaporator coil is getting too cold, which happens when airflow is blocked or refrigerant is low. In Boynton Beach, the most common cause is a dirty coil or clogged filter combined with year-round operation that never gives the system a rest. Turn the system to fan-only mode to let the ice melt, then call (561) 200-8530 before you switch it back to cooling or you risk flooding your ceiling from the overflow.
Telltale Signs
Warning Signs to Watch For
- Visible ice on the copper refrigerant lines going into or out of the air handler
- Ice forming on the outdoor unit near the service valves
- Little to no air coming from the vents even though the system is running
- Water dripping or pouring from the air handler after the system shuts off
- The air coming from vents is warm despite the system running
Root Causes
What Causes AC Freezing Up?
Restricted Airflow Over Coil
The evaporator coil needs a constant flow of warm room air to stay above freezing. When a clogged filter, dirty coil, or closed vent cuts that airflow, the coil temperature drops below 32 degrees and ice builds up fast. In Boynton Beach, where units run nearly year-round, coils accumulate mold and dust rapidly, and a coil that hasn't been cleaned in 12 months can start icing in summer with no warning.
The Fix
Coil Cleaning and Filter Replacement
The coil is cleaned with the appropriate coil cleaner and all airflow restrictions are removed. The technician also checks for any closed or blocked vents that may be reducing return air to the system.
Low Refrigerant Charge
When refrigerant is low, the pressure inside the evaporator drops below normal and the coil gets abnormally cold. At that temperature, humidity in the air freezes onto the coil surface instead of draining away as liquid. In Boynton Beach neighborhoods close to the water, such as those near the Intracoastal Waterway, salt air corrosion causes pinhole leaks in copper line sets that slowly bleed refrigerant over months.
The Fix
Leak Detection and Refrigerant Recharge
The system must be fully thawed before a technician can accurately measure pressures and find the leak. Once the leak is located and repaired, the system is recharged to the correct level and the coil temperature monitored to confirm it stays above freezing.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Restricted Airflow Over Coil | Low Refrigerant Charge |
|---|---|---|
| Filter is clogged and coil is coated in dust | ||
| Refrigerant pressure is below the manufacturer's range | ||
| Ice returns shortly after thawing even with a clean filter | ||
| All supply vents in the home have weak airflow | ||
| Oil residue found on refrigerant line connections |
Free Inspection
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An on-site inspection is the only way to confirm which cause applies to your property. Free, no obligation.
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