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Dead Men Tales: A Disastrous Decision

HeatingHelp Posts: 493
edited August 2022 in THE MAIN WALL
A Disastrous Decision

Have you ever found yourself in some dank basement staring at (and totally appreciating!) the simple beauty of some old, one-pipe, gravity-return steam heating system? And then you decide that this system, which has gotten by without you for nearly a century, should have motorized zone valves. In this episode, Dan Holohan explains why you are doomed on the day that you make this fateful decision and how to recover from it.

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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,925
    I almost did that a long time ago when I was but a wee lad with a set of tools and all the knowledge in the world. Well, at least enough knowledge to get in trouble.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
    EBEBRATT-Ed Member Posts: 13,102
    Did it myself when I knew nothing. A two family took out two boilers and replaced them with 1 boiler and two zone valves.

    Always wondered how it worked.............................................. or didn't work. The customer was an oil customer I don't remember any complaints :#:#:#
  • Jamie Hall
    Jamie Hall Member Posts: 20,424
    Yup. Been there, done that. That's when I started learning about steam... and a fascinating journey it has been.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,782
    I got the impression that Dan had an almost illegal amount of fun telling this story. :p

    Yours, Larry
  • ScottSecor
    ScottSecor Member Posts: 642
    I think I've worked on almost every one of these systems in my neck of the woods. Most were installed in the 1950's or 1960's. Have yet to find one that works as hoped for. We've replaced many operators and valve bodies only to have them last just a few years.

    Apparently God may have made the suggestion of adding steam zone valves because every job I can think of is a church. Wiring, controls and thermostats prove to be a problem as well, must be the devil's work?
    EBEBRATT-Ed Member Posts: 13,102

    Your right. Churches always had them
  • johncreed
    johncreed Member Posts: 3
    Great story!
  • ArthurPeabody
    ArthurPeabody Member Posts: 32
    If motorized zone valves are the problem why not remove them?

    What problem were they meant to solve? What would have been a better solution?
  • Dave_132
    Dave_132 Member Posts: 63
    I had job with a Honeywell motorized valve on a fan coil. Same thing happened with water hammer spitting air vents that would give you a shower. Once i disconnected the valve and left it open the problem went away. We controlled the heat with the thermost. FYI i didnt put the valve in. But what a pain.
    In a world of compromise , some men don't !
  • FrankB101
    FrankB101 Member Posts: 15
    As long as you pipe it properly and install a trap in the right location it is not a problem.
  • Jamie Hall
    Jamie Hall Member Posts: 20,424
    FrankB101 said:

    As long as you pipe it properly and install a trap in the right location it is not a problem.

    Optimist. That works -- sometimes -- on single pipe steam. And, if one takes "pipe it properly" it does on two pipe and vapour as well -- but that simple little three words conceals real thought and understanding. And potential disaster.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JoeEngineer
    JoeEngineer Member Posts: 7
    I have insulated the top floor "attic" apartment in a 6 family building, I have calculated the design heating load to be 1/5 of the radiators' output, thermo pane windows also replaced the single pane windows over the years. Given the 100 + yr old building probably has a heating system sized to heat it with the windows open I though it made sense to replace the radiators with ones that meet the design load, and tack on 20% in case someone needs some fresh air on a cold winter night. My question is am I better off "keeping my hands in my pockets?"
  • mattmia2
    mattmia2 Member Posts: 7,149
    Just supply the water at a lower temp, either directly with a mod con or with any of a number of mixing and boiler protection schemes with a conventional boiler. The lower swt is also reversible if you find you need more heat. Heating up oversized cast iron radiators to far more output than is needed makes keeping the system from overshooting from the residual heat difficult.
  • Jamie Hall
    Jamie Hall Member Posts: 20,424
    The original discussion was steam... is @JoeEngineer talking about a steam system here, or a hot water system?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mikespipe
    mikespipe Member Posts: 28
    for Joe the engineer. I sell a lot of radiators and always have to warn people about undersizing when replacing a big radiator. the exception being the situation you describe. if the only area insulated was the one you described you should be good. the heat needed in that apartment is much less than the others. but the windows, if changed in the entire building, also would reduce the heat load in the rest of the building and you must figure how that effects the balance of the system. It's the balance of the system that is paramount. also make sure insulation is good in the boiler room and any unlived in areas. the systems were designed to be insulated. remember every pipe is a radiator