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

Overhead boiler expansion tank

SethYankSethYank Posts: 9Member
I came across this expansion tank yesterday. The circulator is on the return to the boiler, plugged into a wall outlet. The supply and return from the boiler go into this tank and the house supply and return come into the tank also. I am assuming the piping doesn't connect inside the tank. I am trying to figure out how to purge this system, there in no purge in the return from the house.


  • JUGHNEJUGHNE Posts: 4,962Member
    Possibly a buffer tank?
    For an old gravity system?
    Only one pump?
    Open expansion tank in attic perhaps?
  • SethYankSethYank Posts: 9Member
    only one circulator that i saw, base board heat, piping is 1 1/4 inch copper running horizontal in basement so don't think old gravity, did not get in attic. I am trying to figure out why the water is going to want to go out to the house and not just short circuit in the tank to the boiler.
  • SethYankSethYank Posts: 9Member
    Is this a buffer tank?
  • JUGHNEJUGHNE Posts: 4,962Member
    IDK, just guessing.
    2 pipes in and 2 pipes out?
    Does the label at the air bleeder on the tanks say something about water level?
    Sounds like the pump could run continuously being plugged in like that.

    More pictures of boiler piping probably help.
  • STEVEusaPASTEVEusaPA Posts: 2,328Member
    Well that's 'different'.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 4,510Member
    I suspect there must be another pump
  • hot rod_7hot rod_7 Posts: 9,033Member
    I wonder if there are dip tubes or some sort of diverters/ looks like all the connections down low would just flow across to one another? The air bleeder make me think it is an expansion vessel somehow.

    Was it working when you discovered it? full of water? Any other expansion vessel?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • SethYankSethYank Posts: 9Member
    No the circulator was seized, something about running 365 days a year and not being oiled. the tank was half full right at the air vents. I ran into some one who had seen these before and he said they were a buffer / expansion tank. So there must be another circulator some where, but since the customer thinks I overcharged him for expecting overtime on a Saturday afternoon to replace the circulator I wont be going back.
  • JUGHNEJUGHNE Posts: 4,962Member
    Darn, it was so interesting looking!

    His circ probably quit on a Wednesday and thought it would come back to life......then he calls on a Sat. AM....SOP for many.
  • HVACNUTHVACNUT Posts: 1,595Member
    One of the vets here must have some history on that.
    @SethYank you left us hanging. Get in the box. 2 minutes for instigating.
    How would you even Google that?
  • SethYankSethYank Posts: 9Member
    I dont know that is why I posted it here. some one else has to have seen one of these
  • hot rod_7hot rod_7 Posts: 9,033Member
    where are you located. Often you find more installations like that in an area
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • GordyGordy Posts: 8,489Member
    First experimental attempt at hydraulic separation :)
Sign In or Register to comment.


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