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York Furnace Lockout and Diagnostic Codes

Article ID: 30
Last updated: 14 Feb, 2017

York Gas Furnaces

Re: Lockout Codes

Most 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.

Diagnostic Codes:
Slow Green Normal Operation - no call for heat
Slow Amber Normal Operation - with a call for heat
Steady On Red Control failure
  • Replace control board (S9200U is a suitable replacement)
Rapid Red Twinning error, incorrect 24V phasing
  • Try switching polarity at transformer.
Rapid Amber Low flame sense current
  • Clean flame sensor
4 Amber Y present without G
  • Low voltage wiring problem
1 Red Flame present with gas off
  • Stuck gas valve
  • Shorted flame sensor 
  • Faulty control
2 Red Pressure switch stuck closed
  • Bad pressure switch
  • Inducer fan relay stuck on
3 Red Pressure switch stuck open
  • Bad pressure switch
  • Bad inducer fan
  • Bad inducer fan relay
  • Blocked or restricted vent
  • Condensate drainage issue
4 Red Limit switch open / open fuse
  • Bad limit
  • Low airflow
  • Over-Fired
5 Red Rollout switch open / open fuse
  • Bad switch
  • Cracked heat exchanger
  • Bad inducer motor
  • Over-Fired
6 Red Pressure switch opened 4 times
  • Bad pressure switch
  • Bad inducer fan
  • Blocked or restricted vent
  • Condensate drain issue
7 Red Ignition lockout due to 3 retries
  • Bad igniter
  • Dirty flame sensor
  • No gas flow
8 Red Flame signal lost 5 times
  • Dirty flame sensor
  • Combustion air problem
9 Red Grounding or line polarity fault
  • Try reversing transformer power
10 Red Flame sensed with no call for heat
  • Stuck gas valve
  • Shorted flame sensor 
  • Faulty control
11 Red Extended limit switch open
  • Bad limit
  • Blower failure
12 Red Open igniter circuit
  • Bad igniter
  • Loose wiring to igniter
13 Red 2nd Stage Pressure switch stuck open
  • Bad pressure switch
  • Bad inducer fan
  • Blocked or restricted vent
  • Condensate drain issue

Fault Code Retrieval:  With no thermostat call push and release the LAST ERROR button.  The LED will flash up to 5 stored fault codes, beginning with the most recent.  If there are no codes in memory, the LED will flash two green flashes.

Clear the Fault Codes:  Push and hold the LAST ERROR button for at least five seconds.  The LED will flash three green flashes when the memory has been cleared.

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Article ID: 30
Last updated: 14 Feb, 2017
Revision: 18
Access: Public
Views: 33669
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