Most no-cooling calls on the first hot day of the year come from things that were wrong all winter. A short check in April or May finds them while there is still time to book a visit.
The five checks
- Change the filter. A clogged filter is the most common cause of a frozen indoor coil.
- Clear around the outdoor unit. Rake out leaves and cut back shrubs so there is about two feet of open space on every side.
- Rinse the outdoor coil. Turn the power off at the outdoor disconnect first. Use a garden hose at normal pressure, never a pressure washer, which flattens the fins.
- Check the condensate drain. Find where the line drains and make sure it is clear. If you have a condensate pump, pour a little water in and confirm it runs.
- Test it on a mild day. Once it is above about 65°F outside, run the AC for 15 minutes. Air at the registers should feel noticeably cooler than the room.
Leave these to a technician
- Refrigerant. Checking or adding refrigerant takes gauges and EPA certification. Low refrigerant also means a leak somewhere.
- Electrical parts inside the units. Capacitors hold a charge even with the power off.