Furnace Won’t Start: Quick Troubleshooting + When to Call for Heat Help
Furnace Won’t Start: Quick Troubleshooting + When to Call for Heat Help Disclosure: General information only. If you smell gas, see sparks, or hear loud unusual sounds, stop and call a licensed HVAC pro . Quick Answer Check thermostat mode, power, and filter first. Confirm the breaker and furnace switch are on. If it still won’t start or short-cycles , call HVAC. Stop the Damage First If you smell gas, leave and call from outside. If you smell burning, shut it off and turn off the breaker. Don’t keep restarting a failing furnace . Fast Checks (Most Common Fixes) Thermostat set to HEAT, temperature raised Replace an extremely dirty filter Check breaker and reset once Check furnace power switch (often near unit) Confirm vents are open and unobstructed Listen: does it try to start then stop? What the Symptoms Usually Mean Starts then stops quickly: safety shutdown , airflow issue , sensor Fan runs but no heat: ignition or flame sensor rel...