Furnace displays E9 and cycles on and off frequently without reaching set temperature

Safety first: Turn OFF power and gas before removing burner components. Gas pressure adjustments must be performed by a qualified technician.

• Check gas valve position: Ensure the manual gas shutoff valve handle is fully parallel to the gas pipe. A partially closed valve can cause low flame.
• Inspect burners: Remove the burner assembly if accessible. Look for rust flakes, spider webs, or debris in the burner ports. Clean with a soft brush and compressed air. Do not enlarge burner openings.
• Observe flame: With panels in place, restore power and gas, then call for heat. Through the sight glass, flames should be mostly blue, steady, and not lifting off the burners. Small, lazy, or yellow flames indicate a combustion issue.
• Professional service: Gas pressure and orifice sizing must match Kelvinator specifications. If low flame persists, have a licensed technician measure inlet and manifold gas pressure and verify correct orifices.