Inducer and blower may run; LED flashes six times repeatedly; furnace does not heat.

Safety first: Turn off power before disconnecting tubing or wiring.

• Drain and clear tubing: Remove the rubber tubing from the pressure switch and inducer ports. Blow through the tubing to clear moisture or debris. Reinstall securely.
• Check vent slope and joints: Inspect the PVC vent and intake for proper upward slope away from the furnace and tight joints. Low spots can collect condensate and intermittently block airflow.
• Clean condensate trap and hoses: Remove the condensate trap assembly, flush with warm water, and clear any slime or debris. Reconnect hoses firmly.
• Observe inducer operation: Restore power and call for heat. Listen for the inducer ramping up and staying at a steady speed. If it surges or slows, the motor may be failing.
• If problem persists: The pressure switch rating or IFC timing may be incompatible or failing. A qualified technician should verify correct parts and replace the pressure switch or inducer as needed.