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gonzo71's avatar
gonzo71
Explorer
Oct 08, 2017

Attwood Furnace Help....please

Happy Canadian Thanksgiving

I need some help on my furnace. It's an Attwood 8900-II.

When I put the furnace on I can hear the van come on. After half a minute or so the igniter will come in and I can feel some hot exhaust outside. As soon as the igniter stops so does the warm exhaust and the flame will not light.
The LED on the control board will block 3 times which according to my manual is a ingnition failure (no kidding). What could be the cause.

I did just take an air hose and blow out a lot of roasted flies. Could this be the problem. How do I propperty clean that. I tried to vacuum but still no luck igniting the furnace.

Lucky that I have the AC heat pump. We had snow last night.
Class A
  • gonzo71's avatar
    gonzo71
    Explorer
    Oct 08, 2017
    Old-Biscuit wrote:
    The Spark Electrode provides high voltage spark for ignition.......which is happening (warm exhaust)

    BUT it is also used for FLAME PROOFING....ie: main flame lights off--generates milliamp signal that goes back to circuit board to prove flame lit.
    No signal return....DC gets dropped to gas valve/no flow

    Due to flame lit signal being milliamps
    Spark electrode:
    *Must be engulfed in flame
    *Must be clean..no soot/carbon
    *Must have clean/tight wire connections
    *No cracked ceramic insulator


    You have Good strong spark.....flame IS lighting......Just need to clean up/check spark electrode so milliamp signal can get back to circuit board

    (No thermocouple used.......pilot flame systems use them)


    I have the feeling, with all the roasted flies, the soak electrode maybe full of sud.

    We are on our last trip o the season, the AC heat pump is running OK. I will make the furnace my spring project.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Oct 08, 2017
    The Spark Electrode provides high voltage spark for ignition.......which is happening (warm exhaust)

    BUT it is also used for FLAME PROOFING....ie: main flame lights off--generates milliamp signal that goes back to circuit board to prove flame lit.
    No signal return....DC gets dropped to gas valve/no flow

    Due to flame lit signal being milliamps
    Spark electrode:
    *Must be engulfed in flame
    *Must be clean..no soot/carbon
    *Must have clean/tight wire connections
    *No cracked ceramic insulator


    You have Good strong spark.....flame IS lighting......Just need to clean up/check spark electrode so milliamp signal can get back to circuit board

    (No thermocouple used.......pilot flame systems use them)
  • msturtz's avatar
    msturtz
    Explorer
    Oct 08, 2017
    If I hazard a guess it is the thermocouple. That is what tells the control board that there is flame. Usually it is installed in the bburner area in the path of the flame. They usually have one more two wires that connect to the control board.

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