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Connect PEX to shower valve — Measure and Cut PEX

Beginner

Part of project

How to Replace a Section of Galvanized Pipe with PEX · Step 5 of 7

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In this video

Measure and cut a PEX pipe according to the height of the shower area. Install a conversion fitting to the pex pipe. Place the crimp ring into the fitting. Crimp the ring using a crimping tool.

Goal: Plumbing Pipe Installation (PEX)

  • PEX conversion fitting makes it possible to connect the PEX pipe to the existing copper pipe.
  • Crimp the fitting before connecting to the shower valve.
  • The crimping tool has a crimping gauge which has a go and no go side which can be used to test if the crimping is done right.

Used in this video

  • PEX Pipe Cutter (Cutting Mechanism: Rotating blade)Cutting the PEX pipe.
  • PEX Crimping Tool (Mechanism of Action: Gripping)Crimping the fitting to the PEX pipe.
  • PEX Crimp Ring (Material: Copper)Securing the fitting to the PEX pipe.
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FAQs

How difficult is this project for a DIY beginner, and how long should I expect it to take?

This project is rated for beginners, but it requires careful attention to detail and precision. For replacing a small section, a DIY beginner should realistically budget 2-4 hours, accounting for material gathering, preparation, and thorough leak testing. Factors like pipe accessibility and unexpected issues can extend this timeframe.

What are the most critical safety precautions I need to take when cutting old galvanized pipe and working with water?

Always shut off the main water supply and drain the lines completely before attempting any cuts. Wear appropriate personal protective equipment (PPE), including safety glasses, work gloves, and hearing protection, especially when using a reciprocating saw. Be prepared for residual water and rust flakes to emerge from the old galvanized pipe, and have a bucket and rags ready.

Do I need all the specialized tools listed, or can I use more common alternatives for this PEX replacement?

While specific tools like a PEX pipe cutter and depth gauge are highly recommended for clean, accurate, and reliable PEX connections, some alternatives can be used. A reciprocating saw with a metal-cutting blade is ideal for galvanized pipe, but a pipe cutter can work if space allows. Avoid using a hacksaw for PEX as it can create burrs, hindering a proper seal. Investing in the correct tools minimizes common mistakes.

What are common mistakes DIYers make when connecting PEX to galvanized pipe, and how can I ensure a leak-free joint?

A common mistake is not properly preparing the galvanized pipe end (e.g., failing to clean threads thoroughly, not applying enough pipe dope/Teflon tape) or not fully seating the PEX into push-to-connect fittings. Ensure the existing galvanized pipe end is clean, dry, and free of burrs. For push-to-connect fittings, use a depth gauge to mark the PEX, and push it firmly until it bottoms out inside the fitting, then give it a slight pull to confirm engagement. Test all new connections meticulously before finishing.

Transcript
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take the fitting off from the top of the shower valve. For this particular project, we're going to use pecs, which is a plastic flexible line used especially for water lines. The great thing about pecs is with the conversion fitting, you can connect pecs directly to the copper without much problem at all. Some of you may have a shower valve where the copper is soldered directly into the valve. In that case, all we'll do is cut the copper about midway up, we'll use a specialized sharp-byte conversion fitting and slide the pecs right in place. In our case, we have a screw on fitting, so we'll take this sharp-byte fitting that fits specifically into the pecs, we'll take our ring, put it on here first, and crimp it in place. Now we do this first because we'll never get that crimping tool close enough to the brace in order to get it to fit tight. So let's go ahead and take the tool and crimp the ring on. With the pecs crimping tool comes this handy little gauge. It has a go-side and a no-go side. You want the no-go side not to go on and the go-side to go on. That ensures that you've crimped it tight enough but not too tight.

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