Furnace starts, inducer runs, but burners do not light and E04 is displayed.

Safety: Working on gas components is hazardous. If you smell gas, shut off the main gas supply, ventilate the area, and call your gas supplier or emergency services.

Steps:

• Verify shutoff valves: Confirm the manual gas cock near the Atlantic furnace is parallel to the pipe (open). Check any upstream shutoff valves.
• Check electrical connections: With power off, inspect the gas valve connector and wiring harness from the Atlantic control board. Ensure the plug is fully seated and wires are not damaged or burnt.
• Observe ignition sequence: Restore power and call for heat. Confirm the inducer runs and the igniter glows. Listen for a click from the gas valve. If there is no click and no gas flow, the valve may not be receiving power or the coil is open.
• Professional testing: Measuring gas valve coil resistance and verifying 24 V (or model-specific control voltage) at the valve during ignition requires a multimeter and should be done by a qualified technician. Gas pressure must be checked with a manometer.

Do not: Do not attempt to disassemble or manually open the gas valve. Replace the valve with an Atlantic-approved gas valve assembly if it is confirmed faulty.