York Gas Furnace: PHU 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 Spill...

Gas Furnace: PHU Re: Flashing Code 2 (Assuming original control board) Code 2 = Pressure switch stuck closed The furnace pressure switch should only close when the inducer fan output is energized. If control board is not energizing the inducer fan output and the switch is closed, the board...

Gas Furnace: PHU Re: Flashing Code 3 If, after the vent blower is energized, the pressure switch does not close, the control will keep the blower on and wait for the switch to close. The diagnostic code for this problem is 3 short flashes followed by a pause. ► The diagnostic code will go...

York Gas Furnace: PHU Re: Flashing Code 4 (Assuming original control board) CODE 4 = High Limit or Spill Limit Open If the limit control opens, the burners will be de-energized and the air circulation and vent blower will be turned on until the limit closes. The diagnostic light code...

York Gas Furnace: PHU Re: No Heat - Code 7 Code 7 = Failure to Sense Flame Qty Possible Causes: 7 Dirty Flame Sensor 5 Bad Glow Plug 1 Clogged Burners 1 Bad Gas Valve No or Low Gas Pressure Bad Control Board CHECKOUT: 1....

York Gas Furnace: PHU Re: No Heat - Code 8 Code 8 = Flame Lost 5 Times During a Heat Cysle Qty Possible Causes: 2 Dirty Flame Sensor Clogged Burners 1 Chattering Pressure Switch No or Low Gas Pressure Combustion Air Problem ...

York Gas Furnace: P3HU Re: White-Rodgers 50A50-241 - Rapid Flash / Flashing Continuous Rapid Flash = Flame sensed with no call for heat. In a Rapid Flash situation, the furnace control board thinks that the gas valve is stuck on and flame is still burning without a call for heat. Therefore,...

York Gas Furnace: PHU Re: Burners Ignite & Shut Off Code 7 = Failure to Sense Flame Qty Possible Causes: 2 Dirty Flame Sensor Clogged Burners No or Low Gas Pressure Pressure Switch Trip Bad Control Board Thermostat Cycling ...