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.

outside weatherhead control of tandem steam boilers

Looking for help for control of 2 residential steam boilers which are piped side by side in tandem

this is a 4 family house 100 yr old house.

Is heattimer my only choice?.....is there a cheaper alternate?

Currently, running each boiler on its owm T-stat.



  • SWEI
    SWEI Member Posts: 7,356
    Tekmar 279 will work

    Are they twinned, or does each serve a separate area? 
  • MartinM
    MartinM Member Posts: 2
    Common header

    Yes, they are piped to a common header-

    Are the contacts on the 279 dry?

    will it hurt the 279 to hook both boilers to the contacts?
  • SWEI
    SWEI Member Posts: 7,356
    dry contact output

    240V 5A dry contacts.  Where you wire them depends on how the boilers are set up.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,573
    Tag team boiler system

    Are both boilers the same capacity? You may want to investigate firing them both together, but cutting the 2nd boiler out when its vaporstat senses a few ounces of pressure. when the temperature drops to the design point, then the dropping pressure will enable the vaporstat to fire the 2nd boiler to maintain the minimum pressure.

    The system pressure must be only a few ounces, with maximum main venting, but I think you would find great economy in having only 1boiler firing most of the time.

    I hope I have explained this adequately, but if not maybe someone else will help out.--NBC
This discussion has been closed.