Spring AC Tune-Up Checklist (Before First Hot Day)

Don't wait until 32°C to find out the AC is broken. Here's the checklist we run on a spring tune-up — most of it you can do yourself in 20 minutes.

DIY (you, this weekend, free)

1. **Replace the furnace filter.** A clogged filter restricts airflow on the indoor coil and the AC ices over. Use a quality MERV 11 if you don't have allergies; MERV 13 if you do.
2. **Clear leaves and grass off the outdoor condenser.** Anything within 2 ft of the unit chokes airflow. Spray it down gently with a hose.
3. **Confirm the disconnect is on.** The grey box near the outdoor unit. If you turned it off last fall, flip it back on.
4. **Run the system for 15 minutes at 5°C below room temp.** Air at the supply registers should be 14–18°F colder than at the return.
5. **Check the thermostat batteries.** Dying batteries cause weird short-cycling.

Things a tech checks (us, ~$200, 1 hour)

6. **Refrigerant pressure and superheat/subcool.** Too high = overcharged, too low = leak. Either kills the compressor over time.
7. **Capacitor microfarads.** Capacitors degrade silently. We test with a meter and replace if it's drifted >6% from spec — common cause of "won't start on the hottest day."
8. **Contactor.** Pitting on the contacts = future no-start. Replace before it fails.
9. **Indoor coil cleanliness.** A dusty coil drops efficiency 10–15%. Clean it.
10. **Condensate drain pan and line.** We pour vinegar through to clear algae. A blocked drain floods your basement during the first humid week.
11. **Blower amp draw.** High amps = bearing wear. Catch it before the motor seizes.
12. **Test the safety circuits.** High-pressure cutout, low-pressure cutout, freeze sensor. All three should trip predictably.

When to skip the DIY

If your AC is over 10 years old, just book a tune-up. The components that fail on first hot day (capacitor, contactor) need a meter to test, not eyes.

A $200 tune-up in April is the cheapest insurance against a $1,400 emergency call in July.

Book a tune-up: (416) 258-2460.