Spring AC Tune-Up Checklist for Indiana Homeowners

Every May, Boone County gets hit with two things at once: cottonwood season and the first real heat wave. The cottonwood goes first — white tufts pack condenser coils like insulation. Then the temps swing from 45°F to 88°F inside of three weeks, and every AC in the county fires up on the same Tuesday. By Wednesday afternoon, every HVAC shop in central Indiana has a two-week wait.

A spring tune-up done in April catches the problems before that first 90°F day. Not as a sales pitch — as a logistics reality. Here's exactly what that visit should cover.

Why Spring Is the Right Time (Not Fall)

Fall tune-ups are mostly marketing. Your AC just ran all summer — you already know how it performed. Spring is when it matters: the unit sat idle for six to eight months, capacitors drifted, refrigerant migrated, and cottonwood is actively packing the coil. A tech in April finds a weak capacitor before it fails mid-July. A tech in October finds the same capacitor after you've already sweated through the summer.

Schedule in March or April. By Memorial Day weekend the phones are ringing off the hook and you're looking at a week-plus lead time, possibly longer if we get an early heat event.

Outdoor Unit Checks

Condenser Coil Cleaning

This is the big one in Boone County. Cottonwood from late May through June mats onto the coil fins like a blanket. A clogged coil raises head pressure, makes the compressor work harder, cuts efficiency, and shortens compressor life. A good tech flushes the coil with a coil cleaner and rinses from the inside out — not just a garden hose spray from outside that pushes debris deeper in.

Refrigerant Charge Verification

Low refrigerant doesn't fix itself. If the system is short, there's a leak somewhere. A tech checks subcooling (TXV systems) or superheat (fixed-orifice systems) and compares against manufacturer specs. If refrigerant needs to be added, you should receive a written record of how much was added and the before/after pressure readings. EPA 608 certification is required to handle refrigerant — this is not a DIY task.

Pad Level and Clearance

Concrete pads settle over Indiana winters. A unit that's tilted more than a few degrees can affect oil return in the compressor. Check that it's level. Also clear any vegetation within 18 inches on all sides — shrubs that look fine in April will be pressing against the unit by July.

Indoor Unit Checks

Blower Motor Amp Draw

The blower motor moves conditioned air through your house. A motor drawing near its nameplate amperage limit is running hot and working harder than it should — often because of a dirty wheel, a bad capacitor, or worn bearings. Measuring amp draw with a clamp meter takes 30 seconds and tells you a lot about motor health.

Capacitor Test

Capacitors are the most common AC failure part. They're rated in microfarads (µF) and degrade over time, especially after hot summers. A tech measures actual capacitance with a multimeter and compares it to the rated value stamped on the can. Industry standard: replace if it's more than 6% below rated. A capacitor that tests at 85% of rating today will probably fail at 100°F in July.

Evaporator Coil Inspection

The evaporator coil sits above the air handler. It collects condensation and, if the filter has ever been neglected, dust. A tech shines a light in to check for ice buildup indicators, corrosion, or biological growth. Access is limited on some systems, but even a visual check catches obvious problems.

Condensate Drain Line Flush

The drain line removes the moisture your AC pulls from your air. In Indiana summers, a high-efficiency system can pull one to two gallons of water per hour out of the air. Drain lines clog with algae and sludge. A clog triggers the float switch and shuts the system down — usually at the worst possible time. Flushing with diluted bleach or nitrogen takes five minutes and prevents the most common mid-summer no-cooling call we get.

Electrical Component Checks

Contactor Condition

The contactor is a high-voltage relay that switches the compressor and condenser fan on and off. The contact points pit and burn over time. A pitted contactor can weld closed (compressor runs continuously) or fail to close (no cooling). Visual inspection catches obvious pitting; a good tech checks contact gap and surface condition.

Capacitor µF Test

Already mentioned above for the blower, but the outdoor unit has its own run capacitor (and sometimes a dual-run capacitor serving both the compressor and condenser fan motor). Both get tested. Both fail. A $25 capacitor replaced in April beats a $129 diagnostic call in July.

Disconnect Condition

The outdoor disconnect box should open cleanly, the fuses or breaker inside should be rated correctly for the equipment, and the wiring connections should be tight. Loose connections at the disconnect are a fire risk and a source of intermittent failures that are hard to diagnose.

Airflow Checks

Filter

A clogged filter is the number one cause of reduced airflow, frozen evaporator coils, and comfort complaints. This is the one thing on this list you can and should do yourself — every 30 to 90 days depending on filter type, pets, and household dust load. A tech will check it during a tune-up, but don't wait for an annual visit to change a $15 filter.

Return Duct Static Pressure

Static pressure is the resistance the blower is fighting to move air. A tech with a manometer can measure total external static pressure and compare it to the equipment's rated maximum. High static pressure means restricted airflow — often undersized return ducts, a clogged filter, or closed registers. This reading matters more than most homeowners realize.

Supply Register Temperature Split

A properly charged, properly functioning AC system should deliver air that is 18°F to 22°F cooler than the return air temperature. A tech measures supply and return temps and checks the split. A split that's too small (say, 10°F) points to low refrigerant charge, poor airflow, or an oversized system short-cycling. A split that's too large can indicate low airflow.

Controls: Thermostat and Staging

A thermostat that reads 2°F high or low means your system is running longer or shorter than it should. A good tech verifies calibration and, on two-stage or variable-speed systems, confirms that staging is working correctly — that the first stage runs before the second kicks in, that the variable-speed ramp logic is functioning. A two-stage system that only ever runs in second stage is wasting energy and wearing the equipment faster.

What the Tech Should Give You at the End

This matters. A real tune-up produces a written service record with actual numbers: capacitor µF before and after (if replaced), refrigerant pressures, amp draws, temperature split, static pressure. Not a checklist with checkboxes. Numbers.

If refrigerant was added, you are legally and practically entitled to know how much (in pounds or ounces) and what the system pressures were before and after. Any tech who won't tell you this is hiding something.

What You Can Do Yourself vs. What Requires a Pro

• DIY safe: Change the filter, clear vegetation from around the outdoor unit, rinse the outside of the condenser coil with a garden hose (gentle spray, no pressure washer), check that the condensate drain isn't obviously blocked, replace thermostat batteries.
• Requires EPA 608 cert: Anything involving refrigerant — checking charge, adding refrigerant, recovering refrigerant for repairs. Federal law. There is no exception for homeowners on refrigerant handling.
• Requires electrical competence: Capacitor replacement, contactor replacement, disconnect work. Capacitors hold a charge even with power off. If you don't know how to safely discharge a capacitor, don't touch it.
• Requires equipment: Refrigerant manifold gauges, clamp meter, manometer, capacitor tester. The tools to do this right cost more than a tune-up.

Squadron Maintenance Plan Option

Our Squadron Maintenance Plan covers spring AC tune-up and fall furnace tune-up for $189/year. At $129 for a diagnostic alone, the math works if you're having both done. Plan members also get priority scheduling — which means you're not calling in June wondering why there's a ten-day wait.

Ready to get it on the calendar before the rush? Call us at (765) 894-0047. We'll get you in before the cottonwood flies.