A season-by-season AC maintenance checklist for Jacksonville homes

Why maintenance matters more here

In a lot of the country an air conditioner works hard for three months and rests the rest of the year. In Jacksonville it runs most of the year, and nearly every one of those hours is spent pulling water out of humid air. That water has to drain away, and the dust that comes with it has to go somewhere. Filters load up faster, drain lines grow slime, coils collect grime and small electrical parts work through more cycles than they would almost anywhere else.

None of that fails all at once. It shows up as a system that runs longer, cools a little less and finally quits on the hottest week of the year. Most of what keeps that from happening is simple, and some of it you can do yourself.

Spring: before the muggy season

Spring is the time for the professional visit. Before the heat and humidity settle in, have a technician check refrigerant pressures, test the capacitor and contactor, clean or rinse the outdoor coil, flush the condensate drain, check the indoor coil and blower, and confirm the thermostat is reading and staging correctly. Weak capacitors are the single most common summer failure, and they almost always test weak before they fail.

On your side, put in a fresh filter, clear leaves and grass clippings away from the outdoor unit, trim back plants to give it about two feet of space on every side, and make sure the drain line outside is dripping when the system runs.

Summer: keep it running

Through summer, check the filter monthly and change it when it looks gray, more often with pets or a dusty renovation underway. A clogged filter starves the indoor coil of air, which can freeze it and shut the system down. Keep the outdoor unit clear: mower clippings, mulch and vines all block airflow and make the compressor work harder.

Watch the drain. If the safety float switch shuts the system off or water appears around the indoor unit, the drain line is clogging. Pouring a cup of white vinegar into the drain access every couple of months helps keep slime down. Finally, notice changes: a system that suddenly runs all afternoon without catching up is telling you something early.

Storm season

From June through November, a little storm preparation protects the outdoor unit. Check that it sits level and is anchored to its pad, and clear away anything nearby that wind could throw into it. A surge protector at the unit is inexpensive protection against the lightning and power flickers that summer storms bring.

If flooding is expected, turn the system off at the thermostat and the outdoor disconnect. Afterward, don't restart a unit that sat in water until it has been checked, because water damages electrical parts and compressors. If the yard floods regularly, a raised stand is worth considering.

Fall and winter: heat pump checks

Most Jacksonville homes heat with a heat pump or electric heat strips, and the first cold morning is when weak parts show up. A fall check of the defrost controls, reversing valve and backup heat strips catches most of those problems before you need the heat.

Expect a brief dusty smell the first time the heat strips run each season as dust burns off; a smell that persists, or a burning plastic smell, means shut it off and call. Keep changing the filter through winter, since the system still moves the same air.

What a professional visit should cover

A real tune-up is more than a quick rinse. Expect electrical checks (capacitor, contactor, connections and amp draw), refrigerant pressures and temperatures compared with what the system should show, coil condition indoors and out, drain flush and float switch test, blower and belt or motor check, filter, thermostat operation, and a written note of what was found.

Ask for the readings. A technician who writes down pressures, temperatures and capacitor values gives you a record to compare next year, and that comparison is how slow problems get caught before they turn into breakdowns.

When maintenance isn't enough

Maintenance keeps a healthy system healthy, but it can't fix a system that's undersized for the house, ducts that leak into the attic or a coil that's corroded through. If a well-maintained system still can't keep up, still leaves the house humid, or needs refrigerant every year, it's time for a diagnosis rather than another tune-up.