cutoff/shutdown circuit in steam system (or maybe hot water)

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by rybolt5, Nov 20, 2013.

  1. rybolt5

    rybolt5 New Member

    Messages:
    4
    Location:
    Faribault, MN
    Hi all - I'm renting an old building with steam or hot water heat (think it is steam) and I need to cutoff the unused back space from my retail area. The back space has an entire bank of registers that look to be fed by a single circuit. Can the circuit be killed at a valve (see pic, I think it is a valve) or will there be valves at the registers? Should I do additional work (cut in and place valves). I need help as the cost will kill my business this winter.

    IMG_20131109_095417_881.jpg IMG_20131109_104854_273.jpg

    Thanks. Rusty
  2. Dana

    Dana In the trades

    Messages:
    2,804
    Location:
    01609
    The second picture looks like the valve is on a riser coming out of a Tee, which implies that it's a 1-pipe steam system. (But better pictures would help.) A big hint would be if you hear a hissing sound coming from inside the convector (that's what it's called, not "register") sheet metal when it's heating up.

    If it's 1-pipe steam the pipe will only go in one end of the convector which enters a section of pipe with fins, and a the other end of the fin-tube heat exchanger there will be an air venting valve. Closing that vent will stop steam from entering the convector more reliably than trying to close a rusted up ancient valve on the riser. Steam radiator gate valves are made to only partially block flow, leaving some dribble-room in order to not trap condensate in the radiator- you want to turn it off completely. To do that, you can stop it at the air vent. If you pull the cover it should look something like this:

    [​IMG]

    The silvery-thingy on the riser on the right side is the vent. Close up it'll look something like this:

    [​IMG]

    Some vents adjustable, designed to close when they hit a particular temp, others not, but they are all designed to close up when the steam heats them. But they are often corroded and jammed (usually open)- it's a standard swap-out item. Depending on the design of the existing vent you may be able to just tape over the air-exit holes with aluminium tape, but you may need to just buy a new one (a sub $10 item at the box store for a non-adjustable version) and tape it up the escape holes on the new one. If you need to replace it, take care not to break the old one when you take it out- clean up the threads the best you can and use copious amounts of teflon-tape on the thread to be sure that it doesn't bleed air at the threads. Hand tight is usually good enough- steam systems operate at a fairly low pressure.
  3. rybolt5

    rybolt5 New Member

    Messages:
    4
    Location:
    Faribault, MN
    That's some great stuff - a very thorough reply. Thank you. I'll get dirty now and take the panel off and see what I might see. I have 2-pipe and 1-pipe radiators in my area. Is that common?
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