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Boiler wiring help

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Rsmith83
Rsmith83 Member Posts: 2
in Thermostats and Controls
Trying to cleanup a mess of wiring resulted in me having to buy a new pressuretrol
My question is how to wire this stuff back together correctly.
I have:
- on/off switch
- a switch/transformer?
- Mcdonnell no67 lwco
- spankin new pressuretrol
Pictures included, please help

Comments

  • pecmsg
    pecmsg Member Posts: 4,871
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    I would start with the manufacturer's instructions.

    Make and model are needed!
  • Jamie Hall
    Jamie Hall Member Posts: 23,370
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    Where does the thermostat hook in? Is there an automatic water feeder? Did you take pictures or sketch the wiring before you disconnected things?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,569
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    Lot of unknowns. Is this oil with a 120 volt burner or a gas boiler with a 24 volt valve?

    Basically you start with the electrical panel. HOT, Neutral and ground.

    If you have a remote switch (boiler emergency switch) upstairs or at the top of the cellar stairs go through that first. The switches break the hot wire. The neutral is spliced and goes straight through.

    Then go to the boiler on-off switch.

    If it is oil you may have a thermal cut off switch mounted above the boiler go through that. then through the low water cutoff (terminals 1 & 2) then through the pressure control then to the transformer.

    That is just a very general idea depending on what you have.
  • Rsmith83
    Rsmith83 Member Posts: 2
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    This is a very old steam boiler
    I'm sure it went through all heating sources...wood to coal to oil then to gas where it is now
    Through troubleshooting I came to the conclusion that the pressuretrol and LWCO were not connected to any kind of live current in order to pass inspection.
    The transformer wires go directly to the gas valve along with the thermostat wires

    My thoughts are the hot(R) from transformer go to the #2 terminal on the LWCO with the neutral(C) to the #1 terminal and on the pressuretrol the hot is run as a passthrough
    With all wires going to the burner valve respectively 
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,569
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    Please don't tell me the transformer is wired to the gas valve without any safety controls in the circuit.

    If your running the boiler off the thermostat without a pressure control or low water cutoff in the circuit you could have an explosion or a fire.

    No, the low water cutoff is just a switch. the hot wire goes in the low water cut off through its internal switch and comes out.

    See the attached drawing.

    If you are not sure how to do this call in a professional.

    Your life & your property could be jeopardized.

    Gas boiler should not be fiddled with.
    pecmsgSuperTech

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