AC Tune-Up & Furnace Tune-Up Checklist: What a Real Maintenance Visit Includes

Published by Breathe Clean Air Conditioning & Heating Repair — 24/7 emergency HVAC service. Call (877) 419-3758.

"Tune-up" means very different things at different companies. A $39 special is often a filter change and a sales pitch. Here is the checklist a genuine seasonal maintenance visit should follow, and why each step matters.

Spring: cooling season AC tune-up

• Wash the outdoor condenser coil and clear debris and vegetation
• Inspect and clean the indoor evaporator coil and blower wheel
• Flush the condensate drain, trap and pan; test the safety float switch
• Verify refrigerant charge by superheat/subcooling — not by gauge pressure alone
• Measure compressor and fan motor amp draw against nameplate ratings
• Test capacitor microfarads and replace anything more than 10% out of spec
• Inspect the contactor for pitting and tighten all electrical connections
• Measure total external static pressure to confirm duct and filter health
• Record supply/return temperature split (a healthy system runs 16–22°F)
• Calibrate the thermostat and verify staging and fan settings

Fall: heating season furnace tune-up

• Inspect the heat exchanger for cracks, rust and scale
• Clean burners and the flame sensor; verify a crisp blue flame
• Test the ignitor, gas valve, pressure switch and all limit switches
• Perform combustion analysis and measure CO in the flue and living space
• Verify manifold gas pressure and temperature rise against the data plate
• Inspect the flue, vent pipe, terminations and combustion air supply
• Clean the condensate trap on high-efficiency units
• Lubricate motors and check belts, bearings and the inducer
• Test safety shutdowns and confirm proper blower delay timing
• Verify heat pump defrost operation and auxiliary heat staging

Best timing

Book cooling maintenance in March–May and heating maintenance in September–October. Off-season scheduling gets you better appointment windows and lets small parts be replaced before the first 100°F day or the first hard freeze.

What maintenance actually saves you

Clean coils and correct charge can recover 5–15% of cooling efficiency. Correct static pressure extends blower motor life by years. Combustion testing catches the CO risks you cannot smell. And most manufacturers require documented annual service to honor parts warranties — keep every invoice.

DIY between visits

• Change filters on schedule and write the date on the frame
• Keep two feet of clearance around the outdoor unit
• Pour a cup of warm water down the condensate line monthly in cooling season
• Keep supply and return registers open — closing vents raises static pressure
• Test CO alarms every month and replace them every 7–10 years

Ready to schedule? Find your city in the service area directory or read our AC not cooling guide.