Pull the old filter and write the date on the new one. Use MERV 8-11 for most 35242 homes; MERV 13 only if the system was designed for it. A clogged filter raises static pressure and chokes the entire system.

When · Every 60-90 days during cooling season.

Call a pro · If the new filter is sucked into the return grille on the first run — your return is undersized.

Find the white PVC condensate line at the air handler. Pour 1 cup of distilled white vinegar into the cleanout. Verify it drains within 2-3 minutes.

When · Once before peak summer (April or May).

Call a pro · Standing water, slime, or a triggered float-switch shutoff means the drain needs professional clearing.

With the disconnect pulled (power off), test the dual-rated capacitor with a multimeter. A 35/5 µF capacitor reading 30/4 µF is failing. Replace before it fails completely in July.

When · Once per year. Spring is ideal.

Call a pro · If you do not own a multimeter rated for capacitance, this is a 30-minute pro visit.

Pull the disconnect. Spray the outdoor condenser fins from the inside out with a garden hose (no pressure washer — bends fins). A clean coil drops head pressure 10-30 PSI and runs cooler.

When · Once before peak summer; repeat after heavy pollen or storm debris.

Call a pro · If the fins are bent or matted with cottonwood, a fin comb and chemical coil cleaner from a pro adds years.

Visual inspection only — pitted contactor faces (visible black erosion) cause intermittent compressor starts. A clean contactor is shiny silver across the contact points.

When · Annually. Replace if pitted.

Call a pro · Any sign of pitting or arcing. Cheap part, easy replacement, prevents a $700 compressor failure.

Drop the setpoint 5°F below current temp. Confirm cooling starts within 60 seconds. Listen for the contactor click at the condenser.

When · Once at season start.

Call a pro · If the system does not start, or starts then immediately stops — control or relay issue, not capacitor.

Vacuum dust off return grilles. Confirm air is moving from every supply register. A weak supply (especially upstairs in Hoover or Inverness 2-story homes) is almost always a duct or return-air issue.

When · Annually.

Call a pro · No supply or weak supply at one register — call for static-pressure measurement.

The large insulated suction line should feel cool but never frosted. Frost on the suction line means low charge, low airflow, or a failing compressor.

When · On the first hot day.

Call a pro · Visible ice or frost — turn the system off and call. Running iced equipment damages the compressor.

The condenser disconnect (gray box mounted on the wall) should latch closed cleanly. Wire insulation should be intact, not chewed by squirrels or sun-cracked.

When · Annually.

Call a pro · Any visible wire damage, scorched insulation, or loose lugs — call before running the system.

Total external static pressure should read at or below 0.5" w.c. on a properly designed residential system. Above 0.7" w.c., the duct or filter is choking the system. Cannot be measured without a manometer.

When · Annually if you have a pro tune-up; once after any duct or filter change.

Call a pro · Always — this requires a manometer and trained interpretation.

Subcool reads on the liquid line; superheat reads on the suction line. Both should match the manufacturer charging chart for the day's outdoor temp. Off-target subcool/superheat means undercharge, overcharge, restriction, or airflow issue.

When · Annually with a pro spring tune-up.

Call a pro · Always — this requires gauges and EPA 608 certification.

The suction line foam insulation should be intact and UV-protected. Cracked, sun-baked, or torn insulation costs you 3-7% efficiency and lets condensation drip.

When · Annually.

Call a pro · Replace insulation if torn or compressed. DIY-friendly with foam tape; pro for a full reinsulation.

Look for daylight or dust-streaks at the cabinet seams. Leaky air handlers steal up to 15% of conditioned air. Seal with mastic or UL-181 foil tape.

When · Annually if accessible.

Call a pro · For attic-mounted air handlers in Crestline ranches and Lake Cyrus 2-story homes — usually a pro visit.

Pour water into the secondary condensate drain pan to confirm the float-switch cuts the system off. Saves your ceiling drywall when the primary drain clogs.

When · Annually.

Call a pro · If the system does not shut off when water rises — float switch failed or wired wrong.

Take a photo of the condenser nameplate, the air handler model and serial, and any observed issues. File with your home records.

When · Annually.

Call a pro · Never. This is the homeowner's job.