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runing hot water loop of steam boiler

rolwak Member Posts: 1
how to wire strap-on aquastat in  relay switch  tradeline  r845 with hot water circulator pump


  • Zman
    Zman Member Posts: 7,569

    I am making a few assumptions here.

    In the systems I normally see here it goes.

    The thermostat wires to TT on the relay.

    Hot power 120 volt (line) goes to #1 and #4. This powers the relay transformer and the circulator switch.

    Neutral to #2

    Hot (load) to circulator to #3

    The next part is a little trickier. You want to use The switch at #5 and #6 in series with your aquastat switch to close the TT's on the boiler.

    Run a wire from one of the boiler TT's to #5 on the 845

    Run a wire from #6 to COM on the aquastat.

    Run a wire from N/O on the aquastat to the other boiler TT

    Leave the existing wires on the boiler TT

    I would recommend an aquastat with an adjustable differential set to 10-20 degrees. This will prevent short cycling.

    Post some pics if you are unsure.


    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
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