Furnace displays E15 and shuts down on very cold days

Safety first: Turn OFF power before working on condensate components. Avoid using open flames to thaw frozen lines.

• Inspect drain tubing: Follow the clear or white plastic tubing from the furnace condensate trap to the drain. Ensure it slopes continuously downward with no sags that can hold water.
• Clear trap: Remove the condensate trap and flush it with warm (not boiling) water to remove sludge and debris. Reassemble per Kelvinator instructions.
• Check for freezing: If the drain line runs through unconditioned space, look for ice. Thaw gently with warm towels or a hair dryer on low, keeping electrical components dry.
• Condensate pump: If a pump is used, verify it has power and the float moves freely. Clean the pump reservoir and discharge line.
• Test operation: Restore power and call for heat. If E15 persists, a technician should verify the condensate pressure switch and drain design.