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We are McLennan boiler only goes up to 140°

criv Member Posts: 1
What do you think the problem could be on my wheel McLean boiler it only goes up to 140° even though I have the digital control board set for 200


  • hot_rod
    hot_rod Member Posts: 22,254
    Is the ODR outdoor reset function enabled? That limits temperature based on outdoor temperature.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    HVACNUT Member Posts: 5,861
    edited December 2022
    What digital control board? If it's the Hydrostat 3250 Plus, then check to see if the jumper B is installed. If it is, remove it. Then turn the High limit down to 160°. But given almost zero information,  thats just a stab in the dark.
  • kcopp
    kcopp Member Posts: 4,441
    Tell us more about your system please. What type of radiators? Baseboards? cast iron?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,060
    Does your WHEEL McLennan boiler actual have wheels, are you sure it is not a McLaren with Wheels like a Formula 1, or maybe an IndyCar, or perhaps an Extreme E car?

    If However you have one of the newer Weil-McLain boilers that is using a modulating control system and has outdoor sensing, the boiler may not get to 200° ever... unless you have it connected to an indirect water heater.

    Edward Young Retired

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

  • ethicalpaul
    ethicalpaul Member Posts: 5,729
    Not everyone is able to see or type so they use voice transcription which is a great help to them, so let’s have some grace about it I humbly suggest
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • ScottSecor
    ScottSecor Member Posts: 863
    Post a photo of your boiler and we may be able to help.  Take one from about two feet away and a second photo from about ten feet away