You can fix this
Likely cause: ice on the coil is blocking air
Ice on the indoor coil acts like a wall that air can't get through. Thaw it, then find out why it froze.
Why this happens
Trane, Lennox and Carrier all list restricted airflow as a cause of a frozen coil, and once ice forms it cuts airflow even further. Tom's Guide quotes HVAC experts warning that closing vents can contribute to coil freezing. Carrier says a frozen AC will not fix itself.
How to fix it
- Set the thermostat from Cool to Off, then set the fan to On to thaw the ice. Carrier and Lennox both suggest this.
- Don't chip at the ice or use a hair dryer or heater on it.
- Put towels around the indoor unit and watch the drain pan as it melts.
- Work through the AC freezing up troubleshooter to find the cause before you run the AC again.
If this does not fix it, tell the HVAC technician
- That airflow was weak at every vent and there was ice on the coil or lines.
- Whether the filter was clean and every vent was open.
- Whether it has frozen before.
Build the full list: what to tell the HVAC technician.
Start this troubleshooter over
References (every fact above comes from one of these pages)
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