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"normal" limit setting

Jimbo_5 Member Posts: 218
Have a 1978 CG3 Weil Mclain series 6 boiler.  It heats a single pipe fintube system loop, one floor, 55' long, 20' wide.  There are 2 of these boilers, side by side, one for the 1st floor and 1 for the 2nd.  The question is, one  limit switch is set at 200 degs and the other at 160 degs.  I suspect someone has touched the settings.  But what might be considered "normal"?  And is this a problem?


  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    180 degrees F

    is atypical design temperature, but have seen required temps as high as 210 degrees F.

    Start at 180.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,557

    Do you get hot water from a coil in either of these boilers? If so you need to maintain temp for hot water production. Other than that, I go with the lowest setting that works. The two settings need to be at least 20° apart. The low setting is the temp the boiler will maintain when it's not calling for heat. The high temp is the temp the boiler tries to achieve when the thermostat is calling for heat. The warmer it is outside, the lower you high temp can be. Of course, you don't want to run downstairs every day to adjust temp, so you set the high to keep the house warm on your coldest day. I'd start at 180° and work your way down, but I wouldn't go below 160° for the high.

    If you are getting hot water from a coil in the boiler, that will probably dictate the low setting, so you get enough hot water. Then the high needs to be 20° above that.
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