YORK Furnace Error Codes

Error CodeWhat this meansHow to fix it
Slow green flashThis is normal operation.N/A
Slow amber flashThis is normal operation with a call for heat.N/A
Rapid red flashThis is a twinning error, incorrect 24V phasing.You should check the twinning wiring.
Four amber flashesThe control is receiving a "Y" signal from the thermostat without a "G" signal, and this indicates that the thermostat is wired incorrectly.You should check the thermostat wiring.
One red flashFlame sensed when there was no call for heat.You should check for a leaky or slow closing gas valve.
Two red flashesThe pressure switch contacts that are normally open are stuck in the closed position.You should check for a faulty pressure switch, miswiring, or an open pressure switch contact that didn't close after the inducer was energized.
Three red flashesMany issues could cause this.Check for a faulty inducer, blocked vent pipe, broken pressure switch hose, or a faulty pressure switch.
Four red flashesThe contacts on the main limit switch that are normally closed have opened.You should check for a dirty filter, an improperly sized duct system, an incorrect blower speed setting, an incorrect firing rate, or a faulty blower motor.
Five red flashesThe contacts that are normally closed have opened during the rollout switch. The rollout control is manually reset.If it has opened, you should check to see if there's a proper supply of combustion air. Otherwise, you can inspect the inducer's operation, the primary heat exchanger for a sign of failure, or the burner for potential issues. Remember to reset the switch and cycle power to the control.
Six red flashesAfter the unit began operating, the pressure switch opened four times during the call for heat.The furnace will lockout for 1 hour and then restart.
Seven red flashesThe flame could not be established. The no-light condition occurred three times during the call for heat before locking out.You should check for low gas pressure, a faulty gas valve, a dirty or defective flame sensor, a faulty hot surface ignitor, or the burner for potential issues. The furnace will lockout for 1 hour and then restart.
Eight red flashesThe flame has been lost five times during the heating cycle.You should check the system for low gas pressure, a dirty or faulty flame sensor, or a defective burner. The furnace will lockout for 1 hour and then restart.
Nine red flashesThe line voltage polarity has been reversed or there's a grounding problem.You should check the furnace grounding and the polarity at both the furnace and branch.
Ten red flashesA flame has been sensed with no call for heat.You should check the gas valve as well as the gas valve wiring.
Eleven red flashesThis is usually caused by a failed blower motor or blower wheel.After correcting the failure condition, you will want to cycle power to the control which will reset the hard lockout condition.
Twelve red flashesThis indicates an open igniter circuit.You should check for a disconnected or loose wire, or a cracked or broken igniter.
Steady redThis is a control failure.You should replace the control board.