What AC Tune-Up Involves
The tune-up starts with the basics: checking and replacing the filter if needed, and inspecting the thermostat calibration to confirm it is reading and responding accurately. From there we move into the equipment itself, testing refrigerant pressures against the manufacturer's specification, measuring temperature split across the evaporator coil, and checking amp draw on the compressor and fan motor against their rated values.
We clean the outdoor condenser coil of any accumulated debris, check the electrical connections and tighten any that have loosened from vibration over time, and inspect the capacitor and contactor for wear. Capacitors in particular tend to weaken gradually rather than fail all at once, and a tune-up is often where a marginal capacitor gets caught before it strands a homeowner without cooling on a hot day.
We also check the condensate drain line for clogs, inspect the blower and ductwork connections at the air handler, and verify the disconnect and breaker are rated correctly for the equipment. Every reading is compared against the manufacturer's specifications rather than just checked for whether the system is running, since a unit can be operating and still be well outside its normal performance range.