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Weil McLain Ultra problem

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?


  • Terry O
    Terry O Member Posts: 67
    I sold the Weil Mclain Ultra for many years as a wholesaler and actual have a Series 2 in my own house. I have reduced the CH fan speed like you to meet design and use DHW max output.

    You do not indicate your boiler model other than being oversized.

    Parameter 13 is maximum fan speed for CH (central heat)
    Changing this to 40 restricts the max speed to 4000 rpm effectively reducing boiler firing rate on central heat.

    Parameter 15 is maximum fan speed for DHW.
    Leaving this setting at 52 provides maximum rpm of 5200 and maximum firing rate for DHW.

    These parameters do not directly control temperatures.

    If your issue is boiler temperature for DHW - Check parameter 1 (factory set of 140) and parameter 33 Tplus value for DHW (should be 50) this would give you 190*F for DHW - have these been changed?

    Regarding Central Heat - Parameter 4 sets the Central Heat "Top" temp or maximum temp of heating curve at I believe -4*F
    Parameter 5 sets the Central Heat "Foot" temp or lowest temp at warm weather shutdown (factory setting 70*F) - this should be changed depending on type of system - For example for standard baseboard convectors you would want this at 115-120*F

    Hope this is helpful.
    Terry O