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

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

LWCO 120volt replacement

All, my boiler shut off due to a faulty LWCO. Was told it was 120V and usually they are 24V and he is trying to locate one. ARe the 120V hard to find and is an electrician needed if we put in a 24V instead. Can this be done by yourself? Any recommendations will be helpful. Located in MA and snowing now.



  • GilmorrieGilmorrie Posts: 98Member has 120-V models. If you want to use a 24-V LWCO, you will need an interposing relay.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,631Member
    Both 24 volt and 120volt models are available at any good supply house. It's not an issue getting one
  • steamer02180steamer02180 Posts: 4Member
    So my old on is a Honeywell rw700a1080 120V. What would be the best replacement without having to rewire anything
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,631Member
    PSE-801-120 McDonnell Miller Supply

    That's 120 volt. There are many to choose from
  • FredFred Posts: 7,814Member
    Are you sure the LWCO is bad or is it just that the probe needs to be cleaned/replaced?
  • SeanBeansSeanBeans Posts: 291Member
    I agree with @Fred
  • steamer02180steamer02180 Posts: 4Member
    So looks we might have a strange one??? It’s 120volt with a 24v step down transformer in it. Anyone here of that.
  • ethicalpaulethicalpaul Posts: 662Member
    If this were my system, I'd rip out all the 120 and replace it with 24v stuff. I don't want all that line voltage running around my boiler. Anyone else feel that way?
    1 pipe Utica 112 in Cedar Grove, NJ, 1913 coal > oil > NG
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,631Member
    Gas is usually 24v oil is always 120 volt. Some think all safetys should be in the line voltage if possible. Better class of wiring
  • ethicalpaulethicalpaul Posts: 662Member
    Ahh good to know. But the beauty of 24v is you don’t need that better wiring 😅
    1 pipe Utica 112 in Cedar Grove, NJ, 1913 coal > oil > NG
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,631Member

    I would rather work on 120volt and up any day. Nothing wrong with 24's the way many people install it. Sloppy, strung all over the place, loose connections etc

    Because 24v cant hurt you it gets very little respect from installers and when used to wire safety controls that's not good. Those controls are important no matter which voltage they use
Sign In or Register to comment.


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