How to Get PEX Fittings to Seal

PEX (cross-linked polyethylene) piping has revolutionized plumbing with its flexibility, durability, and ease of installation. However, ensuring a watertight seal with PEX fittings is crucial to prevent leaks and ensure a long-lasting installation. Here are step-by-step instructions on how to get PEX fittings to seal effectively.

1. PEX Pipe: Ensure you have the correct diameter for your project.
2. PEX Fittings: These can be brass or plastic and should match the PEX pipe size.
3. PEX Crimp Rings or Cinch Clamps: Depending on the system you choose.
4. Crimp Tool or Cinch Tool: For securing the fittings.
5. PEX Cutter: To cut the PEX pipe cleanly.
6. Go/No-Go Gauge: To verify the quality of the crimp.
7. Plumber’s Tape (Teflon Tape): Optional, for threaded fittings.

1. Measure and Cut the PEX Pipe
   • Use the PEX cutter to make a clean, straight cut on the PEX pipe. A straight cut ensures a better seal and easier fitting insertion.
2. Slide the Crimp Ring or Cinch Clamp onto the PEX Pipe
   • Before inserting the fitting, slide a crimp ring or cinch clamp onto the PEX pipe. Ensure it’s positioned a few inches away from the end to allow room for the fitting.
3. Insert the PEX Fitting
   • Push the PEX fitting into the pipe until it reaches the pipe’s end. Ensure it’s fully inserted for a secure connection.
4. Position the Crimp Ring or Cinch Clamp
   • Slide the crimp ring or cinch clamp towards the fitting, leaving about 1/8 to 1/4 inch of space between the edge of the ring/clamp and the end of the pipe.
5. Crimp or Cinch the Connection
   • For crimp rings:
     • Place the crimp tool over the crimp ring and compress it until the tool is fully closed.
   • For cinch clamps:
     • Place the cinch tool over the tab on the clamp and squeeze the handle until the tool releases.
6. Check the Crimp with a Go/No-Go Gauge
   • Use a go/no-go gauge to check the crimp. The crimp should fit in the “go” side but not in the “no-go” side. This ensures the crimp is neither too loose nor too tight.
7. Repeat for Each Connection
   • Follow the same steps for each connection in your PEX system. Consistency is key to ensuring a leak-free installation.

• Avoid Over-Bending PEX Pipe: Excessive bending can weaken the pipe and lead to leaks. Use bend supports for sharp turns.
• Inspect Fittings and Tools: Ensure all fittings are free from defects and that your crimp tool is calibrated correctly.
• Use Plumber’s Tape for Threaded Fittings: If you’re using threaded fittings, wrap plumber’s tape around the threads to enhance the seal.
• Test the System: After installation, pressurize the system and check for leaks. It’s better to find and fix any issues before covering the pipes.

Getting PEX fittings to seal properly involves careful preparation, precise execution, and thorough inspection. By following these steps and tips, you can ensure a secure, leak-free PEX installation that will stand the test of time.