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Pipe Fitting Question

Andrew Stern
Andrew Stern Member Posts: 8
in THE MAIN WALL
Hello all..

1. Can someone tell me the allowance to be made for black iron thread engagement at each end of a 1-1/4" pipe. I have to replace a pipe that has fittings exactly 20" face to face.

2. During air-pressure testing of completed residential boiler piping, I found that the small AMERICAN #700 air vents installed atop the air separator and at another location showed some air loss (although the cap was screwed down). Soap bubbles formed strongly at the pressed assembly seam near the top. Is this a normal operation leakage for this type of vent when tested only with air, and would it seal with water in the system? To pressure test properly, should the air releases have been removed and plugged?

Thanks all

Andy

Comments

  • tommyoil
    tommyoil Member Posts: 612
    make up

    #1) 1" make up. 20"+1" = 21"
    #2) Air eliminators eliminate air. Remove them if possible, screw in some plugs and pressure test, and if the old ones are beat, replace them with new when your done. Happy piping!
  • Tony Conner_2
    Tony Conner_2 Member Posts: 443
    Threaded Pipe

    My Audels book says the thread engagement on 1-1/4" is 11/16". Look at a factory nipple, and the last 3 threads are imperfect. Measure from three threads down, to the end and you'll get just about 11/16". 20" plus 1-3/8" (11/16" X 2) will be 21-3/8" end to end. Cut the threads so you get between 3 and 4 turns to hand tight, and it'll fit.

    The "Mechanical Trades Pocket Manual" by Audel has fitting take-away dimenions for screwed pipe up to 2", along with a ton of other really handy information. It's inexpensive, soft cover, and about the size of a pocket novel.
  • Andrew Stern
    Andrew Stern Member Posts: 8


    Thanks for the help in dimensioning the pipe. I had the pipe made up but it came back 1/4" oversize anyway (I should have sent it back)but tried to insall it. I needed a cheaterbar on the wrench to wring it in an get the distance back to the right size.

    I actually order the Mechanical Trades Manual yesterday by coinsidence. Go figure. If anyone is interested it's 9.95 with free shipping at 1-800-775-7672, but it doesn't show on their website www.mtroubleshooting.com

    I don't know if my air vents are shot, but will replace one and see if it behaves differently.

    Thanks again
    Andy
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