When a heat wave rolls across Lake Ontario, a broken air conditioner can’t wait. Try these safe checks first; they fix more problems than you’d expect, and they’ll help us diagnose the issue faster if you need us.
1. Check the thermostat
Make sure it’s set to Cool and a few degrees below the room temperature, with the fan on Auto. Replace the batteries if the display is blank.
2. Replace the furnace filter
Your central AC uses the furnace blower and filter. A clogged filter cuts airflow, reduces cooling and can freeze the indoor coil.
3. Check the breaker and outdoor disconnect
Check your electrical panel for tripped breakers for both the furnace and the air conditioner. Near the outdoor unit there’s also a disconnect box; make sure it’s on. If a breaker trips again, leave it off and call us.
4. Clear around the outdoor unit
Leaves, grass clippings, cottonwood fluff and plants block airflow through the outdoor coil. Keep about 60 cm (2 ft) clear around the unit. With the power off at the disconnect, you can gently rinse the coil with a garden hose (no pressure washer).
5. Look for ice
Ice on the copper lines or the indoor coil means poor airflow or low refrigerant. Turn the AC off, set the fan to On to melt the ice (it can take a few hours), and replace the filter.
6. Check the condensate drain
Your AC removes water from the air. If the drain line clogs or the condensate pump fails, a safety switch may shut the system off. Look for water around the furnace.
7. Open vents and close blinds
Make sure supply vents are open and return grilles aren’t blocked. On very hot days, closing blinds on sunny windows helps your system keep up.
8. Listen to the outdoor unit
If the outdoor fan isn’t spinning, or you hear humming, buzzing or clicking without the unit starting, switch it off and call a technician. It’s often a failed capacitor or contactor, which needs a professional.
When to call a professional
- Warm air after the checks above.
- Ice that comes back, or refrigerant lines that hiss or are oily.
- The breaker keeps tripping.
- The system is over 10–15 years old or uses R-22 refrigerant. It may be time to look at AC replacement or a heat pump.
Lancaster Heating and Cooling offers 24/7 AC repair across Hamilton, Halton and Niagara. Call 905-388-3333. A spring AC tune-up helps prevent most of these problems.
