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Left hand thread on a steam radiator plug???

Steamhead
Steamhead Member Posts: 17,387
as long as all drips are water-sealed before connecting to it, except the one I mentioned above. Don't forget, the boiler-room end of the dry return will drop into a wet return, and you need leftover steam pressure at that point. This leftover pressure must be supplied by a pipe at least as big as the dry return, and the only place you have that is where the steam main connects to the dry return without going thru the loop seal you built earlier.

The leftover pressure will be present in the dry return all the way from the front of the building to the boiler room, where the dry return will connect to a wet return. It will not affect loop seals discharging into the dry return since the pressure will be substantially equal on both sides of the seals. Water will flow thru the seals but steam will not.

An added benefit of doing it this way is you'll be working with smaller-diameter pipe, which is less labor-intensive.

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Comments

  • thfurnitureguy_2
    thfurnitureguy_2 Member Posts: 74
    Left hand Thread on a steam radiator plug???

    Just when you think you think you have it figured out...OK I have an old cast iron radiator. One pipe stream, For some reason the supply pipe was was on the same side as the air vent. looked like it was done that way from the start. The other side had a 2" plug (looked like the end of a beer can) My tought was to un-do the plug, replace it with a 2" to 1.5" bushing, add the new valve and all would be good. I did chip out the old plug after cutting it off. The threads look in good shape just left hand thread. Is there a left hand to right hand adapter?
  • Jim Bennett
    Jim Bennett Member Posts: 607
    LH Thread

    I don't know about adapters but you can get a left by right hand threaded nipple.

    http://www.plumbingsupply.com/leftright.html

    Maybe someone else will have another solution.

    Jim

    There was an error rendering this rich post.

  • thfurnitureguy_2
    thfurnitureguy_2 Member Posts: 74


    So this is somewhat normal. I will check the site or a supply house. thanks!
  • Steamhead
    Steamhead Member Posts: 17,387
    Tom, if that was the one

    sitting in the back room, that end was actually a center section with legs, designed to accept a right/left threaded close nipple to attach it to additional sections.

    Jim's solution will work fine.



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  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,488


    Thats a new one for me. Never saw a left hand thread on a radiator.

    I have seen old jobs that had couplings tapped left hand on one end and right hand on the other-they were used in place of unions.

    ED
  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398
    LHT rad.

    Yes, that is the one. looks like they will ship the part right out. I did some more thinking on the returns. I think that if I lower the front section of return to the floor It will get me out of 2 U seals and all but one seperate drip line to the back. My thought was to step the return back up to the celing where the pipe trench is, just past the office rad (like it is now). That puts all but one radiator dripping into a wet return. I would like to install a flush valve at the radiator in the office. Somthing I could attach a hose to so I can flush out the return from the office rather than the ditch. What would be nice is a threaded cap at the top of the radiator so you could flush the rad. and the return all at the same time. What do you think?
  • Steamhead
    Steamhead Member Posts: 17,387
    Hmmmmmm

    that sounds good, but the hitch is that you need some way to keep the "A" dimension in the boiler room from turning into a "B" dimension. The leftover steam pressure from a 2-inch main does this admirably for a 2-inch dry return, this is what you have now. I'm not sure the 1-1/2" drop riser coming down thru the office would do it.

    You could, however, tie the drips from the drop riser(s) near the front of the building into the bottom of the existing loop seal. Run the drips from the drop risers that end in the tunnel into the boiler room and drop below water level as we talked about. This will ensure that all drips are water-sealed from each other.

    How about putting a tee at the vent on the main that doesn't go thru the loop seal, this way you wouldn't have to drag a hose into the office.

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  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    Yes you have lost the wood guy. What I was thinking is basically removing the 2" elbow at the bottom of the boiler side of my u seal. I would replace it with a 2" T. The out put of that T would extend at the floor (about 18" below water line)back as far as the office radiator. The office radiator would drip into this lowered return. Just past the office rad. the return would go back up to its current location and the big rad. in the blue room would drip into the dry return as it is now. The last rear radiator by the bench in the teardown room would need a seporate drip to the new return in the boiler room. all of the front drips that are located at the high return now would be dropped into the new lowered return except the huge one in the blue room and it would be wet on either side of it. I am not 100% on the A and the B. Is A supply and B return?
  • Steamhead
    Steamhead Member Posts: 17,387
    But

    the drop riser from the blue room is only 1-1/4" or 1-1/2", correct? That might not be enough to keep the "A" dimension in the boiler room from turning into a "B" dimension.

    The "A" dimension and the "B" dimension look similar. Both are at the end of a main where it drops into a wet return. The difference is whether there is "leftover" steam pressure at the top- "A" has it, "B" does not. Without the leftover pressure, water can back up into a "B" dimension and cause banging, uneven heat, water level problems etc.

    If we don't set up our water seals properly we'll turn the "A" dimension in the boiler room to a "B" dimension, since water seals block leftover steam pressure.

    In a one-pipe system where a full wet return isn't possible and the drips need to be water-sealed, you have to have one full-size steam main discharging into the dry return without going thru a seal. This maintains the leftover steam pressure all the way back to the boiler room and prevents problems. In your case the full-size mains connect to the dry return at the front of the building, and one goes thru a seal but the other does not. Install seals on the smaller drips but leave the one big one unsealed. This will make sure you have a big enough pipe supplying the leftover pressure.

    If you're still lost, call me and I'll come back up and go over it again.



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  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    OK, so my options are to have a complete wet return front to back. Would it work if I lowered the front return as mentioned above and ran a seporate drip for the rad in the blue room also? this would leave all drips into a wet return. only the return would have a step in the middle that would go to its origional position where the pipe tunnle is ugly. There would be no drips into this dry section of the return.
  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    Sorry to keep hammering at this question. The origional system had a wet return that both sides of the system L and R joined into the wet return just below the main vents. What I thought of doing, is taking that concept, only this time bring it all the way to the floor. I guess the wet return is a direct pressure connection between the end of the steam main and the boiler. Now if that is true as long as the return stays full of water it should transfer pressure back to the boiler. Will a step up from the front floor wet return and back down to the new floor return at the boiler room stay full of water? That is if there were no drips installed in that elevated section. Also isn't the function of the equalizer tube, back at the boiler, to keep the pressure the same between the steam main and the return? The reason for my mad attachment to the floor position of the front return, is to get rid of the head banger in the basement and avoid building all of the u-seals. It would also be a shorter run of pipe if I could run the seperate drip for the big rad in the blue room toward the front.
  • Steamhead
    Steamhead Member Posts: 17,387
    The Head Banger

    needs to stay where it is, I don't see any other way around it other than excavating the pipe tunnel deep enough that the return will be wet. Also remember that the original return was wet with the old boiler but a return at that height may well be dry with the lower water level of your Burnham. Maybe cover it with some padding.

    But the rest of your plan will work, with one change: Run the blue room drip full size toward the main loop seal at the front of the building, at or slightly above the level of the bottom of the seal. Pick up the remaining drips on the way, and end in the bottom of the loop seal. This will water-seal all the drips, and they will discharge thru the main loop seal into the dry return. Oh yes, almost forgot- fill the seal with water before you start the system or it will bang until it is full.

    A water seal is not a direct pressure connection. Just like a closed steam trap, it cuts off the leftover steam pressure. This is why, on your system, one of the steam mains must access the dry return without going thru a seal.

    In effect, this setup will work something like a False Water Line, except you won't need to run a steam line to equalize it.

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  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    I actually think I understand this. If I replaced the rear elbow at the bottom of the U seal with a reduction T, I could run a 1.5" pipe along the wall and pick up all the drips from the big one in the blue room, forward. is 1.5" big enough?
  • Steamhead
    Steamhead Member Posts: 17,387
    It should be

    there are only two or three drips that would feed into it, right? Also, if you haven't already, put a drain on the main loop seal, then you can flush the whole thing from the blue room forward when needed.

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