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.

DPDT Aquastat

Options
Jerry Valentine
Jerry Valentine Member Posts: 15
in THE MAIN WALL
Does anyone know if they make a DPDT aquastat?  I want to install a coal stoker with a gas boiler and I want the DPDT aquastat to tell the system when the stoker is not being used.  I would mount it on the recirculating line of the stoker and send the sign from the circulator relay through the aquastat and let the aquastat tell which boiler to run depending on the water temperature of the stoker.  So it would have to make one set of contacts on rise (and break the other) and the same set would break on fall ( and make the other).  Without it, I won't be able to separate the signals from each boiler and I'm afraid of tying the signals together for fear of "blowing the transformers" in the controls or messing up computer boards.



Thanks for your help.



Jerry A. Valentine

Comments

  • Robert_25
    Robert_25 Member Posts: 527
    Options
    Do you need an automatic changeover?

    Hi Jerry, will a Honeywell L6006A (or C) do what you're looking for?



    I have an EFM plumbed in parallel with my oil boiler, and I just ran the signal from the zone relay's end switch through a three way toggle. It isn't automatic, but it is just the flip of a switch to fire the oil unit. I have seen others hooked up with relays, and one guy hooked up a thermostat in a cool part of the house to fire the oil boiler if the room temperature dropped too far. Lots of different ways to do it, just depends on what you want to accomplish.
  • Jerry Valentine
    Jerry Valentine Member Posts: 15
    Options
    Yes, I want automatic changeover

    Robert,



    Thanks for your reply.  It was my first thought to use a typical aquastat -- I have found one that has a spdt switch, but I'm afraid to mix the signals from the boilers.  Gas boiler is one of those 96% boilers with computer boards.   I can't take the chance of damaging the board.



    Maybe someone else will have another idea?



    Thanks,.



    Jerry
  • Paul48
    Paul48 Member Posts: 4,469
    Options
    How

    about wiring the thermostat connections of the boiler through a Grundfos clip-on aquastat? Disabled at 105, enabled below 85. About 30 bucks.
  • Zman
    Zman Member Posts: 7,569
    Options
    Cube relay

    Why not use a regular aquastat and a cube relay. Tekmar 003 is one but everyone makes one. You have 2 separate dry contacts with NO/NC. Truly DPDT
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Jerry Valentine
    Jerry Valentine Member Posts: 15
    Options
    Remember dpdt

    Thanks for your reply, but remember I need dpdt so I don't mix signals.  Guess I'll just use a transformer and two dpdt relays -- seems the easiest way out.



    Jerry
  • Paul48
    Paul48 Member Posts: 4,469
    Options
    Is

    there a common element to both boilers that creates the need to enable or disable individual boilers? Wouldn't disabling the gas boiler when the coal stoker is hot be enough?
  • Zman
    Zman Member Posts: 7,569
    Options
    This will work

    The 003 has 8 terminals. 2 energize the coil. The others are, 3 for one contactor and 3 for another. The contactor is common, NO, NC. If the aquastat (powered by any transformer with extra capacity) closes, it will energize the coil. When this happens you can close one set of contacts and simultaneously open another( one boiler is wired c and nc the other c and no).This will turn off one boiler and on the other.

    2 separate poles that can throw both ways

    Voila

    I have used this on wood boilers with gas backup, it works great.



    http://tekmarcontrols.com/accessories/003.html
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
This discussion has been closed.

Categories