York Gas Furnace: P3DH/P3DN Re: Lockout Codes Red Light Status Description On Faulty Control Rapid Flash Low Flame Sense Signal 1 Lockout Caused by Flame Sensed 2 Pressure Switch Stuck Closed 3 Pressure Switch Stuck Open 4 High Limit or...

York Gas Furnace: P3DN Re: Flashing Code 7 Code 7 = Failure to Sense Flame (3 Failed Ignition Attempts) Qty Possible Causes: 2 Dirty Flame Sensor 1 Bad Glow Plug 1 Clogged Burners No or Low Gas Pressure 1 Bad Gas Valve Bad Ignition...

York Gas Furnace: P3DN Re: No Heat - Flashing Code 8 Code 8 = Flame was established but later lost - 5 times. ► This is a Soft-Lockout which will automatically reset after 1 hour. Qty Possible Causes: 1 Dirty Flame Sensor Clogged Burners Bad Gas Valve ...