Frozen AC Unit: Why Ice Forms and What to Do

Why air conditioners freeze, including airflow restrictions and refrigerant-side problems, plus what to do before restarting the system.

Ice on an indoor coil or refrigerant line means the system is not operating normally. Continuing to run it can worsen icing and reduce cooling further.

What to do

• Turn cooling off
• Check the filter
• Make sure vents and returns are not blocked
• Allow the ice to thaw before further diagnosis

If icing returns, professional diagnosis is appropriate. Low airflow, blower problems, coil conditions, and refrigerant-side issues are among the possible causes.

Related: weak airflow and AC repair.

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