The furnace will not start at all; there are no lights on the control board, and no blower or inducer operation.

Safety: Use caution around electrical panels. If unsure, call an electrician or HVAC technician.

• Check breaker:
  • Locate the furnace breaker in the main panel and reset if tripped.
• Verify service switch:
  • Ensure the switch near the furnace is in the ON position.
• Confirm blower door is properly installed:
  • The door must press the safety switch; reseat the door firmly.
• Inspect power connections:
  • With power off, check wire nuts and connections in the furnace junction box for looseness or burns.