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Radiator valves fully open or a hair closed?

bipbap Member Posts: 191
We have a one pipe steam system.
I know radiator valves need to be either fully open or fully closed.
My Dad (to be clear, who is NOT a plumber) always says to open them fully and then turn it back to close it just a hair (not even a 1/8th turn) so that if it gets stuck years from now, you can turn it a little each way to loosen it up.
Does this make any sense?
And does closing it a hair having any impact on the function of steam/air or possibility of trapping and banging noise?

Would love to prove or disprove many of my Dads “theories“ before I pass them down to my kids one day... thanks


  • mattmia2
    mattmia2 Member Posts: 9,413
    edited January 2021
    That is fine. It doesn't need to be jammed as had as you can against the bonnet if the packing is adjusted properly.

    At least for a conventional globe valve. Various forms of improved valves that are usually some form of ball valve may close a significant amount if you turn them 1/8 turn.
  • psb75
    psb75 Member Posts: 807
    Yes! This is a very sound practice, generally with all rotary plumbing valves. Open fully, then turn closed "just a hair", for the very reason your father described. If the valve gets stuck over time in that position, you can then wiggle the valve in BOTH directions to free it up. I do this with also on toilet valves, under-sink valves etc. Of course this works most generally on valves that remain OPEN most of their life. Generally this does not apply as much to valves that remain closed. I don't think this practice applies to ball valves--though it may work on these as well.
  • bipbap
    bipbap Member Posts: 191
    edited January 2021
    Yes these are just standard radiator valves so I just wasn’t sure how much a hair closed it inside and didn’t want to create any issues if steam or condensate couldn’t flow properly 
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    when valves become frozen, you can always try loosening the packing nut to get them to turn again.—NBC 
    JUGHNE Member Posts: 11,021
    To reinforce "Dad's Theory", some valves do not have rising stems to indicate being open or closed.
    So if opened fully and then closed a 1/4-1/2 turn closed, you can tell if valve is open or closed without affecting the flow/position.
    Also this would prevent the internal workings from being jammed up in the open position.

    FWIW, our procedure for fire hydrants is as you turn them off tight and than loosen 1/2 turn so the stem is movable by hand. You put your hand over a 2 1/2" port to fill the suction of the drain down after shutting off.
    You then later check if it is open or closed before removing the caps which does pass some water. These are valves that must be completely open or closed. They have a drain port below grade that is open with the valve between open and closed. If only partially open then the drain port is peeing a good stream underground that eventually comes to the surface making you think there is a leak in the hydrant.
    Fully open will seal the drain down port......probably more info than needed for this question. ;)
  • Jamie Hall
    Jamie Hall Member Posts: 22,916
    For globe valves I certainly buy your dad's theory -- and use it. Ball valves (or for that matter any of the new quarter turn valves) fully open. Gate valves -- fully open or fully closed, then back off just enough to take up the slack in the nut but not move the stem.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 15,317

    Your dad is correct. That is the correct way to operate a valve.
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 979
    Absolutely, especially if the valve is opened cold and then heats up when the system is running, potentially expanding parts within the valve binding them on the backseat.

  • SteamingatMohawk
    SteamingatMohawk Member Posts: 979
    Also, if you backseat a valve when hot, it could bind when it cools down. It all depends on the design of the valve and materials of construction. Just crack it a little bit off the backseat/fully open position.

    However, some valves may have a backseat arrangement to prevent leakage past the stem, so you have to be careful.

    Check this out for info: