A closer look
Ice is a symptom that needs investigation
A frozen coil can be linked to restricted airflow, a blower issue or a refrigerant-side problem. Continuing to cool with ice present can make the problem worse and creates more meltwater when the ice thaws.
The ice needs to clear before some operating checks are useful. Do not chip it away or apply heat; the underlying cause should be found before returning the system to normal operation.
Why an AC coil freezes
- Restricted airflow from a dirty filter, blocked return or weak blower
- Low refrigerant caused by a leak
- A dirty evaporator coil
- A failing blower motor or capacitor
- Running the system at very low thermostat temperatures
How to thaw it safely
- Turn the AC to Off at the thermostat
- Set the fan to On so air moves across the coil and helps it thaw
- Expect several hours to thaw fully, and catch any water that drains
- Replace a dirty filter while you wait
- Do not chip or scrape ice off the coil or lines
Why you should still call
If the coil froze once, something caused it. Thawing it may restore cooling for a while, but if the cause is low refrigerant or a failing part, it will come back. A diagnosis finds the reason.