Pipe fittings: do threaded and press fittings differ?

Water and central heating installation uses various types of pipe fittings. Two of the most popular elements are threaded fittings and press elements. What is the difference between them and what are their biggest advantages?

Table of contents

  1. Pipe fittings - construction and installation
  2. Threaded fittings
  3. Press pipe fittings
  4. Pipe fittings - main differences

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Pipe fittings are among the most important elements of any water installation. PVC fittings and PEX fittings are becoming more popular, being chosen more often than copper fittings. The can be used both in heating (95° C max) and water installation. One of the biggest advantages of a solution of this type is the possibility to transfer drinking water without the risk of polluting it. Regardless of the type, both products can be used to connect a PEX pipe with other elements in water installation. Different types, such as tees and elbows are useful to build larger and more complicated installations.

Pipe fittings - construction and installation

Whether they are PVC fittings, PEX fittings, copper fittings or any other type, their construction is not very complicated. The elements differ only slightly. The main distinction is in the method of installation. See a comprehensive description of threaded and press fittings below.

Threaded fittings

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A threaded fitting consists of the following elements:

  • A threaded nut.
  • Tightening ring.
  • Tube (with sealing o-rings).
  • Dielectric spacer.
  • Fitting body.

Threaded pipe fittings have a threaded nut which needs to be twisted off the dielectric spacer. Then the nut and tightening ring is put on the pipe. The tube should be placed inside the pipe and press it tightly to eliminate any spaces between the two elements (the pipe should be cut in 90 degree angle). If the tube is inside the pipe, the nut should be screwed with hands as tightly as possible and then fastened with a wrench. Be careful not to fasten the nut too much, as it could damage both the fitting and the pipe.

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Press pipe fittings

There are several elements in press pipe fittings:

  • Tightening sleeve.
  • Tube (with sealing o-rings).
  • Dielectric spacer.
  • Fitting body.

Installation of pipe fittings of this type involves putting the tightening sleeve directly on pipe (without dismantling it). Special gaps located in the tube are used to make sure that the pipe has been placed deep enough. To fix the fitting, a special mechanical press tool is used, which is the main difference between the two types. The tool is put on the pipe and turned on. After a few seconds you can hear a characteristic noise - that means that the fitting has been properly connected with the pipe.

Pipe fittings - main differences

As stated in the descriptions above, the main difference between the two systems lies in the method of installation. Threaded fittings are easier to install and they do not require any special tools. Threaded pipe fittings are also cheaper than the other ones (although the difference in pricing is relatively small). An additional advantage is the fact that the fitting can be easily disassembled after the installation.

There are, however, certain limitations. It might happen that after dismantling the fitting, the tightening ring needs to be replaced. Another disadvantage is that after installation the fitting cannot be moved, as it could cause leaking. It is particularly problematic with elbows, as they have to be positioned at a certain angle.

Press pipe fittings are a bit more expensive. Using a mechanical press tool is a safer method of installation (it is easy to fasten a threaded fitting too tight). Pressed pipe fittings (especially elbows and tees) can be moved around after installation. This means that they can be easily adjusted to the next element without the risk of damage. Furthermore, they can be placed in concrete, as they are more durable and stable.

Both of the systems have their strengths and weaknesses. The decision between them depends on one’s individual needs.

PEX fittings - how to install them?

The method of installation for PEX pipe fittings depends on their construction. Before starting the installation process you should make sure which type you own and follow the manufacturer’s instructions.

How to measure pipe fittings?

Measuring pipes and pipe fittings depends on the type of the thread. For male threads, measure the outside diameter. For female threads you should measure the inside diameter.

How to sweat copper fittings?

Start from cleaning the metal and the apply a flux paste. Put the pipe fitting on the pipe and heat the joint so that the flux paste melts and secures the fitting.

How to remove pex fittings?

The easiest way to remove PEX pipe fittings is using a special removal tool. Use it to cut the crimp ring band. Many types, for instance copper fittings can be used again, if they are not damaged.

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