Furnace Maintenance: Homeowner says the furnace had been intermittent twice, inspected and reconnected thermostat wiring. Checked error codes (271, 227). Quoting out pressure switch. Inspected flue Termination for any build up and found plant growing into intake. Flushed the condensate P-trap and drain lines to maintain clear, efficient flow. Checked pressure switch tubing to ensure reliable . Cleaned and polished the flame sensor for optimal ignition. Ran full diagnostics to confirm the system is running smoothly and efficiently. 271 - Soft Lock out, No flame sensed. 227 - Low Pressure Switch Open during trial for ignition.