Status LED shows 7 flashes, furnace may start but shuts down, or will not respond to thermostat.

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

Steps to check:

• Clean flame sensor: Remove the flame sensor and gently clean with fine steel wool until shiny. Reinstall and ensure the sensor tip is in the burner flame path.
• Check burner ground: Verify the burner rack is firmly screwed to the furnace chassis and that there is no heavy rust or paint preventing good metal-to-metal contact.
• Inspect burners: Remove burners if accessible and check for rust, debris, or spider webs in the burner ports or crossover channels. Clean with a soft brush and compressed air.
• Observe flame: After reassembly, watch the burner flame through the sight glass. It should be steady, mostly blue with small yellow tips. Lazy, lifting, or very small flames may indicate low gas pressure or a gas valve issue requiring professional service.