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Overhead boiler expansion tank

SethYankSethYank Member Posts: 9
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 Member Posts: 4,170
    Possibly a buffer tank?
    For an old gravity system?
    Only one pump?
    Open expansion tank in attic perhaps?
  • SethYankSethYank Member Posts: 9
    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 Member Posts: 9
    Is this a buffer tank?
  • JUGHNEJUGHNE Member Posts: 4,170
    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 Member Posts: 1,915
    Well that's 'different'.
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 3,689
    I suspect there must be another pump
  • hot rodhot rod Member Posts: 7,809
    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 Member Posts: 9
    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 Member Posts: 4,170
    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 Member Posts: 1,034
    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 Member Posts: 9
    I dont know that is why I posted it here. some one else has to have seen one of these
  • hot rodhot rod Member Posts: 7,809
    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 Member Posts: 7,780
    First experimental attempt at hydraulic separation :)
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