When to call a professional
A single freeze after a neglected filter may never return once the filter is replaced. If ice comes back within a day or two of a full thaw, though, the cause is likely a leak, a blower problem or a dirty coil, and those need hands-on testing.
Humid summers around Birmingham, AL give a struggling coil plenty of moisture to freeze. Call to get connected with an independent local HVAC provider who can check airflow and refrigerant and talk through refrigerant leak repair if needed.
- Ice returns after the system thawed fully and a new filter went in.
- Frost forms on the outdoor unit's larger copper line during hot weather.
- Airflow from the vents feels weak even with every register open.
- Water from melting ice overflows the drain pan.
What an HVAC provider may inspect
- Refrigerant pressures and electronic leak detection
- Blower motor speed and wheel condition
- Evaporator coil cleanliness
- Return air size and duct restrictions
- Condensate pan and drain function after the thaw
Keeping it from happening again
Fresh filters, open registers and a coil cleaning during routine HVAC maintenance keep air moving the way the system was designed. Avoid closing off many rooms at once, since the coil depends on a steady volume of warm return air.