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Some questions on a system that may have been vacuum at one time.

Double DDouble D Posts: 288Member
It appears this system may have had a vacuum pump. I know once a vacuum system always a vacuum system. I don't see the owner going for the idea of restoring it. It appears it's been running this way for quite some time. In the mean time, one of the zones has failed. The main this zone is on is 4" and it has a 2-1/2" zone valve on it. If I were to remove the zone and bring the main back to 4", will it help the system or would I just be wasting time?


Also on the supply side of the convectors in the classrooms there is some type of fitting or restrictor. Has anyone ever seen one of these and what is its purpose?




Comments

  • clammyclammy Posts: 2,193Member
    Are there traps on those convectors ? I would gather those are restrictions or orifices on those convectors to allow only enough steam into the convector that it will condense even w traps u may see orifices in the convector to help prevent rapid cycling of the trap and only allow enough steam in to satisfy convector. If you where to try and get back to a vacuumed system u would have to get the correct vapor vacuumed vents for the main . I would gather that this system is gravity return then maybe possible but if you have any condensate pumps forget it . I would gather that zone valve head is done since it’s gone mounted up side down I would gather that the motor most likely got wet and shorted and went the way of the dodo bird .converting back vacuume would also require that the boiler is correctly sized and producing dry steam meaning that the boiler near boiler piping should be piped beyond the manafactures minimum piping sizes . Vapor / vacuumed systems like dry steam and perform best w dry steam a vapor vacuumed syem w a mismpiped boiler producing wet steam will not perform well and will cause issues .if there no banging caused by the valve being there I would leave it and as for returning to vacuumed and installing another pump there must be a reason why it wasn’t replaced $ but the money he saved on the pump he paying in fuel usuage and most likely have bad steam distrubition in the building w some areas being over heated while others are cold . The system was most likely designed to use a vacuumed pump if it had one originally . I guess you got some dectictive work to do .peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Jamie HallJamie Hall Posts: 10,021Member
    Yes, removing the zone valve will help. That much restriction will be making that zone heat poorly -- if at all.

    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • clammyclammy Posts: 2,193Member
    If there’s traps and there old and failed open they may be the cause for pump failure .before thinking bout pump replace,Monet I think u would have to be sure your traps ar good other wise steam gonna make it back to the pump and destroy it , I didn’t notice in the beginning that you mentioned vacuumed pump clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Double DDouble D Posts: 288Member
    There are traps on all of the convectors. I have been through the building replacing the cages in the bad ones. When I walked In the door the first time there was steam bellowing out of the vent on the boiler feed tank and the return line was steam hot. The boiler is piped exactly to the manu as l but it is grossly oversized for the connecting load. Steam distribution isn't too bad but burner short cycles. Thanks @clammy.

    Thanks @Jamie Hall I wanted to hear it from someone like you. It made sense to remove it but if it's not going back to a vacuum system I didn't want to go through the work of removing it if it wasn't going to help.
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