Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

McDonnell 67 Boiler Wiring

a1will Member Posts: 23
I stupidly detached my LWCO without taking pictures of what wires were landing where. I have a Mcdonnell 67. There is an autofeeder and the original pressuretrol (American Standard built in 1964). The PO's have the wiring a bit of a mess with an electrical tape and wingnuts in there. I haven't really decifered what they are doing, but I would guess they used the electrical tape to make a jumpered connection like I see on some of the wiring diagrams. I have the auto feeder wired on terminals 3 and 4, and that works properly. I am having trouble understanding how to wire the switches on the lwco and pressuretrol. I think I am just fundamentally not understanding how the switching should be setup as opposed to anything goofy going on. Anyone have any easy to digest diagram/pictures? I have looked at the LWCO wiring diagram and this link and understand I need to make a series circuit between the 3 points (lwco, pressuretrol and finally gas valve) but think I am just being especially dense today. I've wired up plenty of switches in my house wiring but for some reason can't wrap my head around this.


  • Empire_2
    Empire_2 Member Posts: 2,343
    edited October 2015
    Any solutions yet? Just wondering..... Steam can cause quick damage to skin if not totally understood! I just want you to be careful and get on site help from professional SteamHead... The Q; is concerning in and of itself...... All due respect.

    Mike T.
  • JStar
    JStar Member Posts: 2,752
    edited October 2015
    When it comes to safety devices, don't guess or try. Either be certain or call a professional.
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!