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air management

Mark J Strawcutter
Mark J Strawcutter Member Posts: 625
in THE MAIN WALL
an airtrol boiler fitting (ABF)? Might be a problem since I don't think they're being made any longer.

Mark

Comments

  • Mark J Strawcutter
    Mark J Strawcutter Member Posts: 625
    IAS or boiler builtin or both?

    Planning to re-pipe older Burnham boiler pumping away with IAS to airtrol in steel expansion tank.

    Original I&O manual shows relief valve and expansion tank connected to dedicated top-of-boiler tapping. Then again, that manual also recommends pumping _toward_ ponpc :-) Glenn Stanton has confirmed that this particular boiler has a small built-in air scoop at that tapping.

    Can I proceed as planned using the external IAS or will I end up with a collection of air at the builtin scoop with no place to go?

    Should I scrap the IAS and use just the builtin? If so, do I need to try and locate an airtrol boiler fitting (ABF). This could be a problem since I don't think B&G makes them any more.

    Or should I proceed with the IAS/airtrol configuration and bring a line over from the builtin scoop and connect it between the IAS and airtrol? I'd be concerned that this would give me a very large ponpc - everything from the boiler thru the IAS.

    Mark
  • Mark J Strawcutter
    Mark J Strawcutter Member Posts: 625
    kick to top of the wall (nm)

  • [Deleted User]
    [Deleted User] Posts: 0
    Why not

    use the IAS to the Airtrol in the tank? Install a ball valve and auto vent at the built in. Who knows? One might complement the other.

  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,598
    This is

    what I'd do.
    Retired and loving it.
  • Mark J Strawcutter
    Mark J Strawcutter Member Posts: 625
    my understanding

    is that with a steel expansion tank (non diaphram) you want all the air to go into the tank. If you expell the air (as you would with a diaphram tank) you'll end up with a waterlogged expansion tank.

    So if I vent the builtin, won't I end up with a waterlogged tank over time?

    Mark
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,598
    The air comes out of the tank

    because the water in the tank is cooler than the water in the system. The tank water absorbs the air and then gravity circulation between the tank water and system water takes over, moving the air from the tank into the system by way of solution. The Airtrol Tank Fitting stops gravity circulation between the tank and the system and that's what makes it work. The IAS will trap most of the air and send it to the tank, where it will remain.

    The vent on the boiler is important because, without it, some air will gather there and that part of the boiler won't have any water to remove the heat from the metal. This can lead to stress on that section.
    Retired and loving it.
  • Mike Kusiak
    Mike Kusiak Member Posts: 42


    I have a system with a Burnham boiler using the built in air separator to return air to the plain steel expansion tank, as per the Burnham installation manual, and it works fine. Originally system had an automatic air bleed at the boiler air removal tapping, and the expansion tank would lose its air regularly.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928
    Ditto

    except mine (W/M) didn't have the air vent. Installed the B&G Air-Trol at same time I relocated piping and tank hasn't waterlogged since. Seems really important to have all bleeds CLOSED until you get a steady stream of water from the Air-Trol fitting--otherwise it takes even longer to get all the air out of the system. When filling this way don't be surprised if the rads don't fill in the normal orderly fashion (lowest first) so be prepared with helpers with keys--or little hanging buckets if you have them.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928
    Interesting...

    ...sounds really logical.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928
    Still made

    http://fhaspapp.ittind.com/literature/CATALOG-BG.stm#Residential Pumps

    Look for airtrol under "Air Control Devices"
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928
    Forgive me for being dense

    but if the compression tank is connected to the air separator tapping and the tank (and obviously the line leading to it) contains water how could air collect at the top of the boiler without going up to the tank?
  • Mike Kusiak
    Mike Kusiak Member Posts: 42


    Looking at the literature for the B&G ABF, it appears to perform the same function as the boiler's internal separator, by collecting the air at the top of the boiler, and taking the supply water from a point a few inches lower. Im my case, I dont have any ABF, just a direct connection from the air removal tapping, after the tee for the relief valve.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,598
    The external

    IAS or EAS does the job outside the boiler nowadays.
    Retired and loving it.
  • Mark J Strawcutter
    Mark J Strawcutter Member Posts: 625
    I think Dan was

    referring to one of my proposed configurations where I would just put the relief in the boiler-top tap and have an IAS/airtrol/tank connected to the supply.

    Mark
  • Mike Kusiak
    Mike Kusiak Member Posts: 42


    Using the boilers internal air separator makes a lot of sense to me for three reasons. The first is that it is already there for free. The second is that because of the pumping away configuration, the boiler is at a point of low pressure in the system, so air will come out of solution here easily. The third is that it is also the point of highest temperature, in which case the air is least soluble in water, and will come out of solution.
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