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Dettson hydra Electric boiler keeps shutting off

RadopRadop Posts: 2Member
Good day all. Newbie here and hoping someone can help me out.
I have a Dettson electric boiler providing Hot water to my in floor heating system.
The problem Is that the boiler keeps shutting itself off. When the thermostat asks for heat the boiler won’t come on. Here’s what I have checked so far
- confirmed 240 to the unit.
- confirmed 120 at the transformer and 24V from the transformer to the board.
Only thing I can think of is a bad board.
If I remove the fuse on the boiler and put back in the boiler comes on. It does recycle a few times and sometimes stays on for a few hours but then shuts down.

Any ideas. Thanks in advance.



  • pecmsgpecmsg Posts: 805Member
    Sounds like it’s shutting down on a safety.
    Any trouble codes?
  • Jamie HallJamie Hall Posts: 10,550Member
    As Paul, says, sounds like a safety, and by removing and replacing the fuse you are resetting it. The first thing I'd do is check what safeties are present -- I'm not familiar with the unit, but there is almost certainly a high temperature limit on it, and there may be others. Then work to figuring out what is actually shutting the unit down.

    Do you have any way to measure the output and return temperatures? Flow rates?

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • RadopRadop Posts: 2Member
    Thanks for the feed back.
    I am unable to see any safety codes as there is no display window.
    As for water temp it doesn’t go above 100C and the max indicated for it is around 170c
    I agree removing the fuse is just resetting it.
    I think I added a pic of the board not sure.
    The only think I read is the top left is a spot to connect a ribbon cable I guess tobread codes. I don’t have that setup available to me.
  • JUGHNEJUGHNE Posts: 5,731Member
    100 C or 100 F ?
  • neilcneilc Posts: 663Member
    there are no blinking LEDs?
    do you have the manual ?
  • JUGHNEJUGHNE Posts: 5,731Member
    A remote possibility is if you have the electric company that controls demand. I can't imagine them cutting off all stages of the boiler, but if your first stage is defective and their controller wacky, things could happen.
    This has happened, especially with AC during the summer.
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