Before you touch the outdoor unit, switch the power off at the disconnect near the unit. If you are not sure which switch feeds it, turn off the breaker at the panel too. Wait until the fan has stopped. Do not reach into the cabinet while anything is still turning.
Yours to do.
- Clear leaves, grass, and debris from around the cabinet and from the outside of the coil.
- Rinse the fins with a garden hose at low pressure, spraying from the inside out where you can reach. Skip the pressure washer.
- Keep the clear space the manual names around the unit free of plants, stored items, and snow.
- Check by eye that the pad is level and that the unit is not sitting in standing water.
- Watch the condensate drain while the system runs and note whether water is leaving it.
Hand to a licensed technician.
- Anything behind the access panels that holds wiring, the capacitor, or the contactor.
- Any refrigerant work, including checking the charge or looking for a leak.
- Coil cleaning with chemicals, or any method beyond a gentle rinse.
- Ice on the lines or the coil, a hissing sound, or a unit that keeps tripping the power.
Any of those is a reason to call a technician. It is not a reason to start opening the cabinet yourself.
Ask the technician what they will check, and whether they will write the readings into the service notes. Ask for a copy of those notes to keep with the unit's paperwork. Ask which tasks they expect you to keep doing between visits.
Age is a planning input. A repair does not reset the install date you plan around. Find the typical service life on the central air conditioner page, then count from your install record.