York Gas Furnace - Code 1

Article ID: 142
Last updated: 15 Jun, 2020

York Gas Furnace

Re: Flashing Code 1

Code 1 = Flame sensed with no call for heat.

► In a Code 1 situation, the furnace control board thinks that the gas valve is stuck on and the flame is still burning without a call for heat. Therefore, when a control board goes into a code 1, it will lock the inducer motor and blower motor on.

Qty Possible Causes (From Most to Least Likely):
Bad Control Board
Sticking Gas Valve
Shorted Flame Sensor


1. Check Gas Valve

  • Start the furnace with a call for heat
  • After the burners have been lit for at least 30 seconds, remove the "W" wire.
    • The burners should extinguish immediately.
      • Delayed shut-off = Sticking Gas Valve

2. Check Flame Sensor

  • Visually check the flame sensor for rust flakes or other items that may cause a false reading.
  • Check flame sensor Microamps when the burners shut-off.
    • No Microamp signal but controller locks-out = Bad Control Board

This article was:   Helpful | Not helpful
Report an issue
Article ID: 142
Last updated: 15 Jun, 2020
Revision: 12
Views: 834
Comments: 0
Also read

Also listed in