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Goodman furnace starts then stops after 4 seconds

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mbhangi11
mbhangi11 Member Posts: 2
in Gas Heating
1. Flame sensor is r3placed
2. Pressure switch is jumped and verified. Hoses are good
3. Motor seems to be running fine and pushing air out
4. Nice blue flame, no flame issues

What else are we missing. The tech that came by is stumped as well.
Another tech came, tested CO2 in the 4 seconds and says, leak in heat exchange. But the first tech says no way.

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  • HVACNUT
    HVACNUT Member Posts: 5,844
    edited December 2023
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    What's the lockup and manifold gas pressures?
    Natural or LP gas?
    What's the  manifold pressure supposed to be?
    1 stage or 2?
    Check all grounds. 
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,553
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    Your tech needs to find the reason it is shutting down.

    Find out if it is an electrical issue. Are you losing power to the gas valve because an air switch or a safety control is shutting it down?

    Or are you losing the flame while still having power to the gas valve? If so it could be a gas pressure issue.

    Or are you losing the flame signal? Bad sensor, bad ground.

    Does it fail before the indoor blower comes on or after?

    Your tech needs to eliminate these things one at a time. It will take some persistence. Throwing parts at it and guessing don't work.
  • mbhangi11
    mbhangi11 Member Posts: 2
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    Fails before blower comes on.
    Ground is fine, checked all connections.
    Flame sensor is replaced.
    Natural gas.
    I will need to check power to gas valve
  • ratio
    ratio Member Posts: 3,638
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    Combustion hasn't stabilized enough in the first few minutes for a valid reading on an analyzer.
    rick in Alaska
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,898
    edited December 2023
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    Goodman furnace starts then stops after 4 seconds

    Sounds like the flame is not getting proven. The flame sensor must be located in the flame properly and the control needs to be working properly. Since you have already "r3placed" the flame sensor And checked that it is in the flame, then the control that senses the flame must be bad.

    Verify this with a meter to see if you have the proper flame signal voltage, verify the gas valve closed when the flame goes out by seeing of there is 24 volts at the valve 24 volt wires to the valve.

    What is the model number of the goodman furnace, or at least post a picture of the wiring diagram. Need to know if it is spark to pilot, direct spark HSI or honeywell smart valve, ignition system to determine where the problem is on this

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

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