New Thermostat

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HotRod1975
HotRod1975 Posts: 17
edited October 2025 in Thermostats and Controls

purchased this today to replace old mercury therm. I plugged in the R & W set the anticipator inside to .6 as the manual on boiler says and boiler won’t kick on. Do I need to remove the red plastic cap on the back??? Am I doing something wrong?

img-1191.jpeg img-1192.jpeg

Comments

  • Jamie Hall
    Jamie Hall Posts: 27,975

    Hard to say. What does the manual say?

    And why did you replace the old mercury one? Those things last forever…

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Intplm.
  • HotRod1975
    HotRod1975 Posts: 17

    manual says nothing about that part.

    Replaced it because a tech said it’s the reason for short cycling on system

  • HVACNUT
    HVACNUT Posts: 7,784

    You're not showing what the wires are connected to.

    mattmia2
  • HVACNUT
    HVACNUT Posts: 7,784

    And no, leave the red cap alone.

  • mattmia2
    mattmia2 Posts: 18,399

    once we get that sorted out and it is still short cycling, we can ask questions to solve that problem

    Intplm.
  • Jamie Hall
    Jamie Hall Posts: 27,975

    The old thermostat was not the reason for the short cycling…unless someone with busy fingers really messed up the anticipator.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2Intplm.
  • ratio
    ratio Posts: 4,344

    IIRC there'sa cardboard cover over the contacts under the cover. That does get removed if it's there.

    Do post a pic of it inspire installed with the wiring.

  • mattmia2
    mattmia2 Posts: 18,399

    is that lever on the pivot a pendulum for leveling it when you munt it from when they were mercury?

  • JUGHNE
    JUGHNE Posts: 11,653

    Show the wires and also the heat anticipator, thanks.

    mattmia2

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