How do you Union a pipe?

How do you Union a pipe?

To make an effectively working pipe fitting, both the male and female ends are sealed together with the help of nuts. A female threaded fitting has threads on the inside, while in the male-threaded fitting, the threads are on the outside.

What is the difference between a pipe union and a coupling?

Pipe unions and couplings are both types of fittings that allow you to repair breaks in plumbing lines, but there’s an important difference between them: A coupling makes a permanent connection, while a union makes one that can be separated and reassembled repeatedly.

What is a union fitting pipe?

A union is a threaded fitting which allows the pipe work to be separated and reconnected without any horizontal movement in the pipe. It can be a standalone pipe fitting connecting two pieces of pipe, or an integral part of another fitting (such as a ball valve) which allows it to be separated.

How much length does a pipe union add?

The distance between the fittings and the extra reach must be included in the length. If you are using 1/2 inch pipe, add 7/16 inch per end and 1/2 inch per end.

How do you stop a union from leaking?

If the union is leaking from either solder joint, disconnect the union and heat the leaking joint to melt the solder. Slip the union off, spread new flux and re-solder it. If the union is joining copper and galvanized steel pipes, it should be a dielectric union.

How do you install a union pipe fitting?

Thread the male half of the union nut onto the left-side pipe, and tighten it securely. Slip the ring nut portion of the union onto the right-side pipe with the threads facing outward. Thread on the other half of the union nut, and tighten it securely.

What is the reason for using a pipe union in a pipe system?

With a pipe union, the two pipe ends don’t screw into one another—they each screw into a third piece. When one pipe needs to come apart from the other, the union piece simply screws onto one of the two pipes completely.

Why we are use Union in pipe line?

The threaded union makes the connection of the pipeline simpler and easier to disassemble and replace, which greatly saves the cost of the pipeline connection.

Do you use Teflon tape on unions?

Never need teflon on unions, the gasket does the sealing. Some people use A small amount of silicone grease but it is not necessary and could cause problems with the gasket sitting properly.

How much thread allowance should you allow for a 1 inch pipe?

1/2-inch and 3/4-inch nominal pipe size have 14 threads per inch. 1-inch, 1 1/4-inch, 1 1/2-inch and 2-inch nominal pipe size have 11 1/2 threads per inch. 2 1/2-inch nominal pipe size and larger have 8 threads per inch.

How do you seal a stainless steel union?


  1. Use ½” wide tape dope.
  2. Place the end of the tape on the first thread, do not extend past the end of male pipe thread.
  3. When using 3.5 or 4.0 mil tape, wrap three revolutions, A thinner 3.0 mil tape may need four to five full wraps around the pipe.
  4. Make up joint in a normal manner.

How do you seal a pipe union?

Brush off existing sealing tape from the thread that the central holding nut attaches to, using the steel brush. Wrap sealing tape twice clockwise around the thread, and screw the central holding nut back onto the thread. Use the pipe wrench to tighten the central holding nut in place. Turn on the water supply.

Do you tape a union?

not on the union threads, you would only use teflon tape on the connecting pipe threads if its a threaded union. It’s a union that’s glued to pvc pipes on both sides.