Furnace does not respond to thermostat; Miller LED flashes 7 times in a repeating pattern.

Safety: Turn off power and gas before removing burner components. If you suspect gas pressure issues, contact your gas supplier or a licensed technician.

• Clean flame sensor: Remove the flame sensor and gently clean the rod with fine steel wool until shiny. Reinstall and ensure the mounting screw is tight to provide a good ground.
• Check burner flame: With panels in place and power restored, observe the burner flame through the sight glass. Flames should be steady, mostly blue, and evenly distributed. Yellow, lifting, or wavering flames indicate combustion or gas issues.
• Inspect burner and orifices: Remove burners and clean any rust or debris. Check orifices for partial blockage and clean carefully with a soft brush (do not enlarge the holes).
• Verify ground connections: Ensure the burner rack and control board ground wires are secure to the furnace chassis. Poor grounding can cause weak flame sensing.
• Call a professional for gas pressure check: If problems persist, a technician should measure inlet and manifold gas pressure and adjust or correct supply issues.