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

How can I disable the low limit aquastat now that I’m not using the tankless coil?

Options
ericmhurtado
ericmhurtado Member Posts: 53
in Thermostats and Controls
Hello,
I have a WM SGO 3 oil fired steam boiler with a hot water baseboard zone and I just got installed an electric heat pump water heater for DHW and do not need the tankless coil. How can I disable the Honeywell L4006A low limit aquastat that is connected to the coil? I have attached a pic. Can I just connect the two wires that are powering the aquastat with a wire nut? Thanks

Comments

  • lchmb
    lchmb Member Posts: 2,997
    Options
    just remove one wire..
  • Jamie Hall
    Jamie Hall Member Posts: 23,280
    Options
    Do not connect the two wires together! Then the boiler will think you need heat all the time. It's a switch... as @lchmb says, just disconnect (and cap) one wire.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Scott M_2
    Scott M_2 Member Posts: 26
    Options
    Wait you said you had a hot water baseboard connected also?depending on the wiring you may still need that low limit.
  • ericmhurtado
    ericmhurtado Member Posts: 53
    Options
    Why would I need the low low limit to keep working?
  • HVACNUT
    HVACNUT Member Posts: 5,834
    Options
    From what I see in the pic, yes, you can remove the L4006A for the coil.
    You have an aquastat for the hydro loop.
    Shut off the power and disconnect the wires for the coil aquastat completely.
    TT on the burner?

    And relocate the wire to the hydro aquastat. That front access door gets pretty hot.

    When the heat is off for the season, the boiler will sit idle.
    With an oil boiler that not a great situation.
    Have the boiler serviced in the spring, brushed and vacuumed. Boiler, chamber, chimney base. This way in the fall everything should be dry and ready to go.
  • ericmhurtado
    ericmhurtado Member Posts: 53
    Options
    Thanks for all of the helpful advice.
    I believe the STEAM thermostat is connected to the burner but there is also another thermostat connected to a relay for the hot water loop.
    I’m not sure I follow HVACNUT. Are you saying I should disconnect the wires from the low limit, disconnect the high limit wires and cap them and then connect the low limit wires to the high limit? Could you please let me know how would the hot water loop work after I make this adjustment as I’ve been having issues with getting the high limit to reach temp as burner shuts off way before it hits 180? Thanks
  • ericmhurtado
    ericmhurtado Member Posts: 53
    edited January 2019
    Options
    HVACNUT said:

    From what I see in the pic, yes, you can remove the L4006A for the coil.

    You have an aquastat for the hydro loop.

    Shut off the power and disconnect the wires for the coil aquastat completely.

    TT on the burner?

    I did disconnect BOTH wires ON the aquastat, not on the burner. Is this ok? Can you please let me know what I should do next as I didn’t understand the rest of your comment.
  • ericmhurtado
    ericmhurtado Member Posts: 53
    Options
    I disconnected the wires from the low limit to the tt terminals on the oil primary, the r7184p. This totally disabled the low limit aquastat and it no longer fires the burner to maintain temp on THIS aquastat. I also cut both the cold and hot piping to the tankless coil. Thanks to all for the helpful advice with this discussion.

Categories