pex a, b or c?

[Innovate1]

Getting ready to plumb a half bath and wondering which PEX I should use. Pex A appears to be able to be expanded or use crimp rings. I plan to use crimp rings which means I could use the cheaper PEX B. But B apparently is not as flexible and may kink easier. It can't be used with the expansion connection method but that's not an issue for me. Not sure about the other pros and cons other than B is about half the price of A. Both are cheap enough to no be a big difference for the amount I need. PEX C is apparently less common.

 

[Showkey]

These two links pretty much spell it out......Seems B wins ??? Depends if you have expansion tools as well.

https://www.pexuniverse.com/types-of-pex-tubing

https://www.pexuniverse.com/types-of-pex-fittings

 

[nadogail]

I would ask my plumbing supplier

 

[joablynn]

PEX A, B, and C tells us what method was used to crosslink (X) Poly Eyhylene (PE) tubing.

PEX A is extruded hot with an arc running through it and achieve about 80% (if my memory is correct) molecular cross linking. PEX A is by far the most durable and flexible and accounts for roughly 30% of the PEX sold world wide. One major advantage of PEX A is that due to the high amount of cross linking, it has a thermal memory. Any damage to the pipe that doesn't actually cut the wall can be repaired simply by heating it. It also allows it to be expanded over a fitting that it will retract onto and continue to grow tighter for at least the next thirty years. It is also a little more chemical resistant, so it's specified in some labs.

PEX B is made from a cold extruded PE that is then immersed in a vat of hot water to achieve something like 30-40% molecular cross linking. The cold extrusion method is faster and cheaper, making PEX B a lower cost product. PEX B continues to grow market share because of its low cost, but has few other benefits. PEX B has little thermal memory, so it must be mechanically fastened and kinks or other minor damage cannot be repaired.

PEX C is made from a cold extruded PE that is essentially microwaved to achieve something like 50-60% molecular crosslinking. In practice, it's much like PEX B, but is slightly more flexible and rugged.


Realistically, any of these products will work just fine for most projects. I prefer PEX A as it gives the most installation flexibility and I prefer piping systems with fewer fittings.

Once the system is installed, it's possible that a PEX A system will outlast the PEX B system, but it will likely be long after you and I are in our graves.

 

[johnnyradiant]

Pex A kink - Heat with heat gun till clear and let cool naturally = good to go.

 

[UltimatE]

Pex B is by far the easiest for a DIY / Homeowner install as everything you need is readily available at the home centers. Downside is lack of flexibility, crimps aren't as good as shrink fit, and fittings reduce the ID which restricts flow. Seeing as this is only for a half bath, you're probably not too concerned with flow to a toilet or a sink, so that's not a big issue IMO.

Pex A is definitely better than B, however its going to be more expensive. The materials are more and it requires the purchase of special expansion tools. The pros are higher flexibility, repairable, higher flow fittings that are the same ID of the tubing, and the shrink fit collars are more reliable. Pex A is generally only available at plumbing supply stores which can be an issue if you don't have one close to you.

ETA: Pex B is also more forgiving with the connections, you can still move the connections slightly after the crimp is made, so if you have to rotate a 90 or a 45 you can do so. You can also completely dry fit everything with Pex B as the fittings go into the tubing and can be removed by hand. Pex A connections have a slightly higher learning curve as you have to make sure you expand them enough and then quickly put the fitting in and get it into place.

TL;DR ... If you're just doing a half bath, Pex B will work just fine. If you were going to plumb a whole house I would suggest making the step up to Pex A.

 

[Firebrick43]

Pex B is by far the easiest for a DIY / Homeowner install as everything you need is readily available at the home centers. Downside is lack of flexibility, crimps aren't as good as shrink fit, and fittings reduce the ID which restricts flow. Seeing as this is only for a half bath, you're probably not too concerned with flow to a toilet or a sink, so that's not a big issue IMO.

Pex A is definitely better than B, however its going to be more expensive. The materials are more and it requires the purchase of special expansion tools. The pros are higher flexibility, repairable, higher flow fittings that are the same ID of the tubing, and the shrink fit collars are more reliable. Pex A is generally only available at plumbing supply stores which can be an issue if you don't have one close to you.

ETA: Pex B is also more forgiving with the connections, you can still move the connections slightly after the crimp is made, so if you have to rotate a 90 or a 45 you can do so. You can also completely dry fit everything with Pex B as the fittings go into the tubing and can be removed by hand. Pex A connections have a slightly higher learning curve as you have to make sure you expand them enough and then quickly put the fitting in and get it into place.

TL;DR ... If you're just doing a half bath, Pex B will work just fine. If you were going to plumb a whole house I would suggest making the step up to Pex A.

You can use f1807 fittings(crimp) on pex A(or B/C) but you can only use f1960(expand)fittings with pex A. Pex A can easily be purchase from supply house.com for minimal cost over b/c from the lumber yard and is worth the extra coin even if using crimp fittings.

I really don’t know how expanding could be any easier, slip the sleeve on, let the tool expand 7 times and drop the fitting in. other than greasing the mandrel no maintenance is needed.

F1807 (crimp) needs a go-no go gauging of rings(mainly ignored which sometime serious consequences) and possible adjustment depending on the quality of tool(or lack of). I have seen more than my share of crimp leaks (always fail the go/no go gauge) but never a expand fitting.

 

[rust buster]

You can use f1807 fittings(crimp) on pex A(or B/C) but you can only use f1960(expand)fittings with pex A. Pex A can easily be purchase from supply house.com for minimal cost over b/c from the lumber yard and is worth the extra coin even if using crimp fittings.

I really don’t know how expanding could be any easier, slip the sleeve on, let the tool expand 7 times and drop the fitting in. other than greasing the mandrel no maintenance is needed.

F1807 (crimp) needs a go-no go gauging of rings(mainly ignored which sometime serious consequences) and possible adjustment depending on the quality of tool(or lack of). I have seen more than my share of crimp leaks (always fail the go/no go gauge) but never a expand fitting.

This! Pex A is awesome used with the propex system. The propex expansion tool (milwaukee makes this in M12 and M18) is fast, idiot proof, and has increased flow compared to crimp fittings.

 

[UltimatE]

You can use f1807 fittings(crimp) on pex A(or B/C) but you can only use f1960(expand)fittings with pex A. Pex A can easily be purchase from supply house.com for minimal cost over b/c from the lumber yard and is worth the extra coin even if using crimp fittings.

I really don’t know how expanding could be any easier, slip the sleeve on, let the tool expand 7 times and drop the fitting in. other than greasing the mandrel no maintenance is needed.

F1807 (crimp) needs a go-no go gauging of rings(mainly ignored which sometime serious consequences) and possible adjustment depending on the quality of tool(or lack of). I have seen more than my share of crimp leaks (always fail the go/no go gauge) but never a expand fitting.

Agreed.

Really it comes down to if OP wants to invest in the expansion tool. If he is OK with dropping $400 for the ProPex tool, and has access to local supply or waits for shipping, by all means go to with Pex A. It is definitely superior. If he doesn't want to invest in the tooling, Pex B will suffice as long as he pays attention to his crimps.

Personally I would invest in the tool and not deal with potentially leaky crimps.

 

[Showkey]

PEX A .....tool Cost is 10x plus:

Highest price (100-160% higher than PEX-B)(1).
Lower bursting pressure than PEX-B.
Possible residual or leaching chemicals from manufacturing process.
Variation in wall thickness.

It’s not slam dunk by a long shot. Especially for a small job DIY project.

 

[shellback]

Pex seen through the eyes of a noob.

Started on my 1st bathroom renovation and decided to test my Pex skills.
Aside from unclogging the *******, I’ve never done any plumbing and the only fixture I’ve ever fixed was a sharkbite toilet supply valve.
I decided on Pex-A Uponor. I got totally outfitted with the $400 M12 Milwaukee tool kit; 100’ of 1/2” Uponor pipe; expansion fittings; cpvc to pex a fittings (had to search quite a bit to find Pex-A specific); cpvc glue; pipe bender bracket; and a ratcheting pex pipe cutter. I did not get any 90-degree fittings as I had plenty of room to curve the Pex-A between the studs. All I used to keep the bend clean was to install the support brackets to maintain curvature. Oh, and also 1/2” clips to keep the pipes secured.
Installation was glorious!

Testing was flawless but there was a small hint of chemical smell while the water flowed. Hopefully it wears off.

 

[topcok88]

Did all the plumbing on the water heater that arrived yesterday and used the Viega PexPress system and it’s near idiot proof - push the tube in past the window to ensure it is fully seated, place the tool around the crimp ring area and press. It took maybe 5 minutes to press every connection at the Manabloc.



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