You can fix this
Likely cause: the thermostat isn't calling for heat
If the thermostat isn't on Heat, or is set below the room temperature, the furnace has no reason to light.
Why this happens
Trane lists the thermostat first among the reasons a furnace won't ignite, and its not-turning-on page puts simple setting mistakes at the top. A thermostat set below the room temperature, or left on Cool or Off, never sends the call for heat.
How to fix it
- Set the mode to Heat and the fan to Auto.
- Set the temperature a few degrees above the current room temperature.
- If the thermostat runs on batteries and the screen is dim or blank, replace them.
- Wait a couple of minutes for the furnace to start.
If this does not fix it, tell the HVAC technician
- What the thermostat was set to.
- Whether the furnace started once it was set to Heat.
- The thermostat brand and model.
Build the full list: what to tell the HVAC technician.
Start this troubleshooter over
References (every fact above comes from one of these pages)
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