The 24-Point Spring Cooling Tune-Up Checklist for Techs

Before the Truck Moves: Filter Sizes, Job History, and Parts on Board

Preparation makes or breaks a spring tune-up. Before you even start the engine, pull up the job history for the address. Did the client report hot spots last August? Were there condenser wash notes or blower assembly issues on the last fall visit? Check the last two years of records, not just the most recent call. Customers remember what you fixed, or skipped.

Next, confirm the filter sizes for every system on-site. Many houses have more than one return, and it is common to find mismatched filter sizes written on old work orders. Stock at least two of each size, including any oddball 1-inch or 2-inch pleated filters. If the system uses a media cabinet, make sure you have a new cartridge on board.

Pack critical replacement parts: dual run capacitors, contactors, relays, a few common fuses, and a tube of pan tablets or strips. Some techs carry a spare universal defrost board and a float switch. If you run out of time or a part fails mid-visit, you will be ready. The goal is to avoid callbacks that eat into summer install season.

Keep reading: What a Two-Visit Maintenance Plan Really Costs to Deliver

Outdoor Unit: Coil, Fins, Fan Blade, Contactor, and Capacitor

Visual Inspection and Cleaning

Start with a complete visual sweep around the condenser. Remove leaves and debris from the base. Trim back vegetation at least one foot from the coil surface. Check for animal nests under the fan guard or in the control compartment.

Disconnect power. Remove the top cover to access the coil and fan assembly. Inspect coil surfaces for dirt and matted grass clippings. A quick rinse with a garden hose, spraying from the inside out, lifts most debris. For heavy buildup, use a foaming coil cleaner labeled for outdoor use. Never bend the fins with a brush or high-pressure spray. If you see bent fins, straighten them gently with a fin comb.

Mechanical and Electrical Components

Spin the fan blade by hand. It should turn freely, with no grinding or wobble. Check the blade for cracks and the set screw for tightness. Inspect the fan motor wiring for brittle insulation or rub marks.

Open the control panel. Look at the contactor: pitted or burned contacts mean it is time to replace. Confirm that all wire connections are tight. Test the run capacitor with your meter. Compare the measured microfarads to the label. Most manufacturers allow a tolerance of plus or minus 6 percent. Below that, replace the capacitor before it fails in July heat.

Electrical: Amp Draw Against Nameplate RLA and FLA

Compressor and Fan Motor

After reassembling and restoring power, measure the running amperage of the compressor and condenser fan. Use a clamp meter on each load wire. Compare readings to the nameplate data: RLA (Rated Load Amps) for the compressor, FLA (Full Load Amps) for the fan motor. Normal operation is usually 60 to 80 percent of these values. High readings warn of overloading or restricted airflow, while low readings can indicate a weak capacitor or failing motor windings.

Check the line voltage at the disconnect, both with the system off and running. Voltage drop under load can mean loose lugs or undersized wiring. If you see more than a few volts difference, investigate further.

Low-Voltage Controls

Inspect the low-voltage wiring for UV damage, rodent bites, or loose splices. Gently tug each thermostat wire and look for corrosion at the connections. Replace cracked or brittle wire. Confirm that the control circuit fuse is the correct size and type, and test for continuity.

Keep reading: Ride-Along: Nine Fall Furnace Tune-Ups in One Day

Airflow: Total External Static Pressure and Blower Setup

Static Pressure Test

Before adjusting refrigerant, get a reading on the system's airflow health. Drill test ports in the supply and return plenums if they are not already present. Insert a digital manometer probe before the coil and after the filter. Add the two readings: this is your total external static pressure, measured in inches of water column. Most equipment is rated for 0.5 inches, but some variable speed systems tolerate up to 0.8. If your reading is over the manufacturer's limit, it can choke airflow, drive up amps, and lead to coil freeze-ups.

Blower and Filter Check

Inspect the blower wheel for dust and lint. Even a quarter inch of buildup can lower airflow and raise energy costs. If needed, remove and clean the wheel. Check that the blower motor is set to the correct speed tap for cooling. Too low a speed starves the coil and spikes superheat. After confirming the filter is new and properly seated, button up the air handler.

Refrigerant Charge: Superheat and Subcooling Without Guessing

Get accurate line set temperatures with your digital probes, and use a calibrated manifold gauge set. Record the outdoor dry bulb and the indoor wet bulb temperature at the return grille.

Superheat for Fixed Orifice Systems

For systems with a fixed metering device, calculate the target superheat using a reliable chart based on indoor wet bulb and outdoor dry bulb readings. Measure suction line temperature a few inches from the service valve. Subtract the gauge suction pressure (converted to temperature) from this value. The difference is your superheat. Compare to your target. If the reading is high, charge is low or airflow is restricted. If it is low, you may have overcharge or a flooding coil.

Subcooling for TXV Systems

For systems with a thermostatic expansion valve, use subcooling to confirm charge. Measure liquid line temperature at the service valve. Subtract this from the gauge liquid pressure (converted to temperature). The difference is your subcooling. Compare to the manufacturer's target, often 8 to 12 degrees. If subcooling is high, check for overcharge or a restriction in the liquid line. If it is low, add refrigerant slowly and recheck.

Do not fall back on guessing by sight glass bubbles or coil frost. Always use measured readings and temperature-pressure charts.

See how SeasonTuneUp handles this for hvac and mechanical trades

Condensate: Pan, Trap, Float Switch, and Drain Line

Primary Pan and Trap

Remove the blower access panel and shine a light into the primary pan. Look for rust, standing water, or algae growth. If the pan is dirty, vacuum or wipe out debris. Fill the trap with water to prime it and check for leaks or clogs. A dry trap is a common cause of nuisance float switch trips.

Secondary Pan and Float Switch

If there is a secondary pan, inspect for water stains and confirm the drain is clear. Test the float switch by lifting it: the system should cut out or the thermostat should show an error. If it does not, troubleshoot the switch and wiring. Pour water through the primary drain and watch for a strong, steady flow outside or at the plumbing stack. If you see slow drainage, clear the line with pressurized nitrogen or a wet vac. Add pan tablets or strips to prevent future algae growth.

Thermostat, Controls, and Safety Switch Verification

Check the thermostat for level mounting and tight wire connections. If it is battery powered, replace the batteries. Verify programming for cooling mode and setpoints. Cycle the system through a full call for cooling: the outdoor unit and blower should start and stop as requested.

Inspect all safety switches: high-pressure, low-pressure, and condensate cutoffs. Bypass each briefly to confirm they open and close the control circuit. Where access is possible, test the compressor time delay and any crankcase heaters for proper function.

Document any non-standard controls or add-on devices, such as Wi-Fi modules or zoning panels. If something is not working, note it for the homeowner and your office.

The Written Handoff: Readings, Photos, and the Next Appointment

Every tune-up ends with a clear, written record. Record all your readings: static pressures, amperages, capacitor values, refrigerant temperatures and pressures, and drain line status. Use photos for critical items: before-and-after coil shots, measurement readings, and any defects or repair recommendations. This protects your company and helps the next tech who visits this system.

Summarize what was completed, what was found, and what needs to be watched. If you replaced parts, list them. Note the size and type of filters installed. If you made any adjustments to charge or blower speed, document the new settings. Leave a copy with the homeowner and upload the details to your dispatch or CRM system.

Before leaving, schedule the fall maintenance visit. Use your company's scheduling tool or app to lock in the next appointment. Customers appreciate knowing what comes next, and preset visits keep maintenance agreement renewals on track.

Automated tracking and scheduling tools now make it easier to keep every agreement up to date and ensure no tune-up slips through the cracks. Solutions that handle renewal reminders and booking can free up office staff and help techs focus on delivering a thorough, checklist-driven service every time.