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Gas Furnace - Code 1 / Won't Ignite

Article ID: 252
Last updated: 05 Nov, 2021

Goodman Gas Furnace: GMPN

Re: Code 1 / Won't Ignite

Code 1 = 3 Failed Ignition Attempts


Qty Possible Causes:
3 Tripped or Bad Rollout (Bad Heat Exchanger)
1 Dirty Flame Sensor
4 Bad Ignitor
1 Bad Control Board
Tripped or Bad Stack Over-Temp Switch
Bad Gas Valve
1 Excessive Inlet Gas Pressure


CHECKOUT:

1. Check Ignition Sequence

  • If necessary, reset the furnace lockout by cycling high voltage or low voltage power.
  • Initiate a call for heat from the thermostat and monitor the ignition sequence.
    • The inducer motor should start with no difficulty.
    • The pressure switch should close within a couple seconds of the inducer starting.
    • The glow plug should energize within 30 seconds of the pressure switch closing.
    • The gas valve should power and open within 20 seconds of the glow plug energizing.

2. Check Ignition

  • Visually inspect the burners during ignition.
    • The burners should light smoothly with little or no delay from the glow plug to the flame sensor.
    • Make sure the flame sensor comes in good contact with the flame.

3. Check Glow Plug

  • Look for any visual cracks.
  • Test resistance of the glow plug.
    • No Resistance = Bad Glow Plug
  • Start an ignition sequence.
  • Check for 120VAC power on the 2-wire plug feeding the glow plug during an ignition sequence.
    • No Power = Bad Ignition Control
    • Power Present + No Glow = Bad Glow Plug

4. Check Control Board Output

  • Re-start the furnace with a call for heat from the thermostat.
  • After the glow plug starts to heat-up, check for 24VAC from terminal 7 (Purple) of the molex plug on the control board to ground.
    • Approximately 15 - 20 seconds after powering the glow plug, the control board should send 24VAC power out terminal 7 to the gas valve.
      • No Power = Bad Control Board
      • Power at Board + No Power at Gas Valve = Tripped Limit ⇒ Check each manual-reset Roll-Out Limit (around the burners) and the Stack Limit (vent outlet).
        • If a roll-out is tripped, suspect and check for a Bad Heat Exchanger.
        • If the Stack Limit is tripped, suspect a Clogged or Restricted Vent.

5. Check Gas Pressure / Valve

  • Inlet Gas Pressure
  • Turn off power to the furnace and check the inlet gas pressure.
    • Minimum Pressure = 5" w.c. for Nat. gas, and 11" w.c. for propane.
    • Maximum Pressure = 15" w.c. (Excessive pressure may lock the gas valve closed).
      • Low Pressure = Bad Meter or Regulator
      • High Pressure = Bad or Wrong Regulator
  • Re-apply power to the furnace and activate a call for heat.
  • Make sure the inlet gas pressure stays above minimum when the gas valve energizes.
    • Pressure Drops Below Minimum = Bad Meter/Regulator or Restricted Gas Line
  • Manifold Gas Pressure
  • Activate a call for heat and monitor the manifold gas pressure during an ignition attempt.
    • Normal Pressure = 3 - 3.5" w.c. for Nat. Gas, 9 - 11" w.c. for LP
      • No Gas Pressure = Bad Gas Valve or Excessive Inlet Gas Pressure
      • Low Gas Pressure ⇒ Increase Manifold Gas Pressure
      • Normal Gas Pressure but No or Delayed Ignition = Clogged Burners Remove burners and clean spreaders

6. Check Flame Sensor

  • DO NOT clean the flame sensor before testing!
  • On the multi-meter:
    • Switch the test leads to "COM" and "mA".
    • Set the meter on DC 200ù.
    • Check the reading when the burners ignite.
      • Minimum acceptable reading = 1 MicroAmp
        • Low Reading ⇒ Clean Flame Sensor & Re-check
        • Normal Reading (2 to 6 mA) but Shuts Off = Bad Control Board
    • MOVE SENSOR LEADS BACK TO "COM" and "V" BEFORE PROCEEDING!
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Article ID: 252
Last updated: 05 Nov, 2021
Revision: 28
Views: 71
Comments: 0