Troubleshooting
Diagnose your HVAC problem in 5 minutes.
Symptom-by-symptom guides written by a senior technician. Tells you what to check yourself, what to call us for, and which symptoms are actually safety emergencies.
Furnace Blowing Cold Air
Most often a flame sensor problem, a dirty filter, or the thermostat fan switch left on 'On' instead of 'Auto'. Check those three before calling.
Read diagnosisFurnace Won't Turn On
Check the thermostat batteries and the furnace power switch first — they fix half of these calls. Then check the breaker, then the door safety switch.
Read diagnosisFurnace Short-Cycling
Furnace turning on and off every 2–4 minutes is short-cycling. Most common causes: clogged filter, oversized unit, or a flame sensor that needs cleaning.
Read diagnosisFurnace Banging or Booming Noise
Banging on startup is usually delayed ignition — gas pools before lighting and ignites with a pop. Stop running the furnace and call us. It's a real safety issue.
Read diagnosisAC Blowing Warm Air
Most common cause is low refrigerant from a leak. Don't keep running it — you'll damage the compressor. Other causes: thermostat set wrong, frozen indoor coil, dirty filter.
Read diagnosisAC Freezing Up (Ice on the Lines or Coil)
Ice means low airflow or low refrigerant. First fix: replace filter, turn off AC, wait 2 hours for ice to thaw. If it freezes again, call us.
Read diagnosisAC Leaking Water Inside
Almost always a clogged condensate drain line. Pour 1 cup of vinegar through the cleanout port. If still leaking, the drain pan or P-trap may be cracked.
Read diagnosisWater Heater: No Hot Water
Gas: check the pilot light or burner ignition. Electric: check the breaker, then the upper element. Both: confirm the temperature setting hasn't been bumped.
Read diagnosisWater Heater Leaking
Where the leak is matters. Top connections = a fix. Around the temperature/pressure relief valve = adjustable. From the tank itself = replace, today.
Read diagnosisThermostat Not Working
Replace the batteries first. Then check the breaker for the HVAC system. If both are fine and the screen is blank, the thermostat itself or the wiring is the issue.
Read diagnosisStrange Smell From Furnace
Burning-dust smell on first run of the season is normal. Sulphur or rotten egg = gas leak, get out and call the gas company. Burning plastic = call us.
Read diagnosisHouse Too Humid in Summer
An oversized AC short-cycles and doesn't run long enough to dehumidify. Other causes: dirty coil, undersized return ducts, no dedicated dehumidifier.
Read diagnosisLoud Air Conditioner Outside
New noise = new problem. Banging is usually a loose part. Buzzing is electrical. Hissing is refrigerant. Grinding is the compressor — turn it off.
Read diagnosisNo Hot Air From Some Vents
If only some vents are weak, it's a duct or static-pressure issue, not the furnace. Check for closed dampers, kinked flex duct, or a clogged filter.
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Stuck on a symptom not listed? Call us.
Most GTA calls get same-day service. Call, text, or request a fixed quote — we'll come back with a real ETA.
Mississauga, ON · Greater Toronto Area and up to 2 hours out — London, Kitchener, Barrie, Kingston, Niagara.