How to make a PEX-AL-PEX compression fitting connectionTools and materials required:
- PEX-AL-PEX tubing
- PEX cutter
- PEX-AL-PEX compression fitting(s)
- PEX-AL-PEX reamer
- (2) Adjustable crescent wrenches or similar (12-14”)
Step 1: Cut the pipe
|Position the pipe cutter perpendicular to the pipe and make a smooth, clean cut.||Cut pipe should be free from burrs.|
Step 2: Ream the pipe
|Select appropriate size reamer inlet and insert it fully into the PEX-AL-PEX pipe.||The edge of the pipe must touch the reamers’ blade as shown.|
|While holding the pipe, firmly push the reamer in and give it 2-3 full turns (in any direction). Shavings indicate that the procedure is being performed properly.||This is how the reamed pipe should look like. Reaming returns the pipe to its’ original round shape and prepares it for installation of the fitting.|
Step 3: Install the compression fitting
|First, slide the compression nut over the pipe. Second, slide the split O-ring as shown on the picture.||Fully insert the main body of the PEX-AL-PEX compression fitting into the pipe.|
Step 4: Tighten the compression nut
|Slide the nut and O-ring toward the fitting and tighten the compression nut over the fitting by hand (~ 2 full turns).||Position one crescent wrench over the fitting and the other over the compression nut. Tighten the compression nut (~ 1-1.5 full turns). You can use a marker to indicate a starting point.|
Step 5: Connection is complete
|This is how a finished connection should look like. Always inspect the fitting visually after the work is complete.|
Frequently Asked Questions:Q: Is PEX-AL-PEX reamer necessary? Can I use a standard pipe reamer?
A: PEX-AL-PEX reamer performs (2) functions – it reams the pipe inside and outside (which can be done with a standard pipe reamer), but also returns the pipe to a round shape, which cannot be accomplished with a standard pipe reamer. Since PEX-AL-PEX tubing can be deformed when being bent or cut, it must be “rounded” in order for the fitting to fit inside the pipe properly.
Q: Are PEX-AL-PEX compression fittings reusable?
A: It is possible to disconnect the fitting but it could be quite difficult, and so for practical reasons the answer would be no.
Q: Are these fittings suited for potable water applications?
A: No. They do not meet the lead content limitations and therefore are not approved for potable water use.
Q: Is there a possibility of over- or under-tightening the fitting?
A: If you follow the instructions above, the risks of over- or under-tightening are very small. Since all systems must be pressure tested prior to being put into use, it is possible to tighten the fitting more if there’s a leak at the connection point. In order to avoid over-tightening the compression nut, do not use excessive force and wrenches larger than indicated when installing the fitting.
Q: Should I apply any thread sealant, Teflon tape or glue to the compression fittings’ threads?
A: No. Not only these are unnecessary, they may compromise the integrity of the connection. Thread sealant and tape can (and in fact, must) be applied over the MNPT/FNPT threaded portion of the fitting, which connects to another pipe or fitting.
Q: What must be the minimal opening of the wrench?
A: For 1” PEX-AL-PEX fittings, which is the largest size we carry, the compression nut requires a minimum of 25/16” (or 1-1/2” and 1/16”) opening. Adjustable pliers (like the Channellock®) can also be used.
Q: Which connection method is better for PEX-AL-PEX – compression or press?
A: Press fittings are more expensive and require an expensive PEX tool, but are quicker and easier to install and therefore are best suited for high-volume installations where pricing is not an issue. Compression fittings require somewhat more time and labor but cost substantially less and do not require a special PEX-AL-PEX tool. You can find more information on different PEX connection methods here.
Q: I see that the brass O-ring is split - is it normal?
A: Yes. When the compression nut is tightened, the open ends of the O-ring come together, exerting pressure upon the PEX-AL-PEX pipe, allowing it to be compressed over the fitting's barbs.
Q: What purpose do the black rubber O-rings over the fitting's barbs serve?
A: The O-rings are intended to prevent water leakage. The main purpose of the barbs is to prevent the fitting from popping out under pressure from the pipe. The O-rings should not be removed from the fitting, nor is it necessary to lubricate them in any way.