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Weil Mclain Ultra

Lakewood Member Posts: 7
I'm having a problem that my Weil Mclain ultra is not resetting. Error code U 1.25. Any suggestions?


  • wogpa67
    wogpa67 Member Posts: 238
    Display shows U124 or
    Display stays on U124 or U125 1 Check transformer. If good:
    Turn off power to the boiler.
    Disconnect thermostat wires at boiler.
    Replace F3 fuse.
    Determine cause of fuse failure on 24-volt system.
    Replace defective part and retry.
    2 If problems persists, check low voltage terminal strip and wire harness.
    Replace if necessary. Retry.
    3 If problem persists, replace control module.

    But it's usually the control module.
    you should have received the updated control supplement which the above is directly from.
  • Reynz_2
    Reynz_2 Member Posts: 98
    Weil McLain Ultra Parameter Setting.
    I have an oversized boiler, and reduced the perimeter 13 setting to 40, however, left the perimeter 15 setting to 52. Meaning, that my boiler did a DHW call should provide 190° heat, but it does not. It seems to be reduced to the fan speed I use for home heating. I checked the setting and it seems fine to me. Any suggestions?
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    Why not start a new thread on this, for more clarity.--NBC