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3_tons's avatar
3_tons
Explorer III
Mar 28, 2014

Furnace issues

My Atwood 15/22 2 speed furnace is acting up. Battery voltage is 12.8v confirmed, but furnace lights up but burner then shuts down after a short period. The led at the furnace is blinking twice which indicates (per manual) igniter problem, yet furnace does initially fire up. I've tried doing a reboot (power off) and a reset at the furnace (cover removed). I don't know where or how to access the sail switch. Any ideas are greatly appreciated.

3 tons

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  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Mar 28, 2014
    Problem isn't with sail switch.

    Sail switch has to make up otherwise furnace will NOT even try to spark let alone fire off.

    When it fires off a mili-volt signal is generated via the main flame. This signal gets sent back to circuit board by the spark electrode/high tension wire to 'prove' main flame is lit so circuit board will keep power on gas valve to hold it open.

    Yours is sparking and lighting off but losing 'flame proofing' signal.

    Dirty spark electrode
    Spark electrode not being engulfed in main flame
    Cracked ceramic causing signal to go to ground
    Poor connection on high tension wire

    Clean up electrode with some emery cloth
    Check position of electrode
    Wipe down high tension wire with a rag with silicone spray on it
    Clean up connector on high tension wire at circuit board.

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