Furnace will not start at all; no lights, no display, no fan operation.

Safety: Before resetting breakers, ensure there is no burning smell or visible damage.

Steps:

• Check breaker: Locate the furnace breaker in the electrical panel. If tripped, reset it once. If it trips again, do not continue resetting.
• Verify service switch: Ensure the furnace disconnect or service switch near the unit is in the ON position.
• Door switch: Confirm that the blower compartment door is properly closed and engaging the safety switch.
• Inspect internal fuse: With power off, check any line fuses inside the Atlantic furnace and replace with identical ratings if blown.

Note: Repeated fuse or breaker trips indicate a short or overload that requires professional diagnosis.