York Gas Furnaces: PT9 Re: Status Codes / Fault Codes These York gas furnaces have a control board inside the furnace blower compartment that will flash a diagnostic code that shows the operating status of the furnace. Status/Diagnostic Codes: Slow Green Normal Operation - no...

York Gas Furnace: PT9 Re: Flashing Code 3 Code 3 = The 1LP pressure switch contact did not close during 1st stg heat operation, or the 2LP pressure switch contact did not close during 2nd stg heat operation ► The 1LP switch is typically rated for 0.75" w.c. and the 2LP switch is typically rated...

York Gas Furnace: PT9 Re: Flashing Code 4 Code 4 = Main limit switch has opened its normally closed contacts. The control will operate the supply air blower and inducer while the open limit condition exists. ► If the limit switch has not closed within five minutes, the control will assume...

York Gas Furnace: PT9 Re: Flashing Code 5 Code 5 = Roll-out switch has opened its normally closed contacts or low voltage fuse blown. The control will operate the supply air blower and inducer while the open limit condition exists. ► The primary limit is wired in series with the roll-out...

York Gas Furnace: PT9 Re: Flashing Code 6 Code 6 = Pressure switch opened (Code 3) 4 times during a run cycle. ► This is a "Soft Lockout" which will automatically reset after 1 hour. ► There are 3 pressure switches on this furnace. 1LP (1st Stage Switch) and 3LP (Condensate Switch) are...

York Gas Furnace: PT9 Re: No Heat - Flashing Code 7 Code 7 = Flame could not be established. This no-light condition occurred 3 times (2 retries) during the call for heat before locking out. ► The furnace will lock out for one hour and then restart. Qty Possible Causes: ...

York Gas Furnace: PT9 Re: No Heat - Flashing Code 8 Code 8 = Flame was established but then lost - 5 times. ► This is a Soft-Lockout which will automatically reset after 1 hour. Qty Possible Causes: Dirty Flame Sensor Clogged Burners No or Low Gas Pressure ...

York Gas Furnace: PT9 Re: Flashing Code 9 Code 9 = Indicates reversed line voltage polarity, reversed low voltage wiring, or Grounding problem Qty Possible Causes: 1 Loose Ground Missing Ground Reversed Line Voltage ("Hot" on white) Reversed Low...