York furnace blower runs continuously; LED shows 8 flashes.

Safety: Turn off power and gas before working on ignition components.

• Power reset: Turn off furnace power for at least 30 seconds to clear lockout. Restore power and call for heat while observing the ignition sequence.
• Watch the sequence: Inducer should start, then ignitor should glow, then gas valve should click and burners light. Note at which step it fails.
• Check ignitor: If the ignitor never glows, test it for continuity with a multimeter. Replace with a York-compatible hot surface ignitor if open or visibly cracked.
• Gas valve and supply: If ignitor glows but no flame, verify gas shutoff is open. If other gas appliances work, the gas valve coil or control board output may be faulty and should be tested by a technician.
• Clean flame sensor: If burners light but shut off quickly, clean the flame sensor as described in other entries.