Step #2 — Inspect the filter. See if it is wet. If so, the water melting off a frozen evaporator coil is not emptying into the drain pan. Place some towels on the floor to avoid water damage as the ice thaws.
Step #3 — See if the filter is dirty. If the filter is clean, you have a problem that will require you to contact a qualified air conditioning technician. If dirt is clogging the filter, discard it and go to Step #4.
Step #4 — While the air conditioning unit is turned off, turn the fan on. This provides more airflow over the frozen coil, which will help it thaw out faster.
Step #5 — Go to a local home improvement store and purchase a new filter but avoid purchasing an expensive one. Buy a filter that costs $10 or less. You do not want to purchase an expensive allergy filter at this time because it will restrict air flow and the system needs as much air flowing as possible until it has thawed out.
Step #6 — When you return home, look at the copper lines outside and the coil inside to make sure the ice is melting. Sometimes the ice may need a couple of hours to thaw completely, so be patient if you still see ice.
Step #7 — Install the new filter and turn the AC system on.
Step #8 — Inspect the system periodically over the next several hours. If you notice that ice starts to form again, turn the unit off and call a local repair service for help from experts in the industry.