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have heatmaker boiler/waterheater when temp falls fast boiler wont come on unless you run hot water no out side cotroll,has set back thermo. after running hot water boiler runs fine


  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    The SPDT

    domestic hot water switch needs replaced.
  • Slimpickins
    Slimpickins Member Posts: 323
    Tim is correct

    The part is actually called a low limit switch and is part # 2400-016 and Laars carries the part. It's very easy to replace, just pay attention to the color coded wires when you disconnect. The clip can be tricky, it's good to add a dab of thermal paste too. 
  • homer
    homer Member Posts: 1

    Before you get the new one push the one you have now down as far as you can towards the tank and wrap insulation around it. Also make sure there is no air in the top of the tank with the coil in it, 
  • AMH112181
    AMH112181 Member Posts: 25

    My favorite tool on a heatmaker is a sazall when i cut them out.
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