You can fix this
Likely cause: the furnace switch or door panel
Furnaces have a power switch nearby and a safety switch behind the front door panel. If either is off, the furnace won't heat.
Why this happens
Trane lists the fuel supply and power among the first checks for a furnace not blowing hot air. Honeywell notes that a furnace door safety switch cuts power when the door panel isn't fully seated, and warns never to tape, bypass or disable it. The switch exists so the furnace can't run with its cabinet open.
How to fix it
- Turn the furnace power switch on. It often looks like a light switch on the furnace or on the wall nearby.
- Press the front door panel firmly into place so it sits flush. Don't tape or hold the door switch down.
- Check the furnace breaker, opening only the hinged panel door. Reset it once if it's tripped; if it trips again, leave it off and call a technician.
- Set the thermostat to Heat and give the furnace a minute or two to start.
When to stop. If the breaker trips again, or the furnace still won't heat with power restored, call an HVAC technician.
If this does not fix it, tell the HVAC technician
- Whether the switch was off or the door panel was loose.
- Whether a breaker tripped and whether it held after one reset.
- Whether the furnace heated normally after you fixed it.
Build the full list: what to tell the HVAC technician.
Start this troubleshooter over
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