Expansion or Crimp

[Deano2002]

being that I had a leak under our bathtub where it teed off to the bathroom sink and the shower controls I had to completely tear the whole tub out and I'm going to just replace all the 35 year old plastic piping. I've seen plenty of pictures with crimp fittings on rv's but none with the Uponor expansion fittings and the plastic collar. Is this an industry standard to go crimp because of vibration possibly?

 

[Isaac-1]

35 year old is probably gray Polybutelene not PEX, its diameter is slightly different than PEX so needs different fittings and crimps, though at this point it should all be torn out and replaced. There was a BIG class action law suit about use of Polybutelene pipes in the late 1990's. Finding proper Polybutelene fittings today may be nearly impossible, though as of a few years ago Sharkbite made Polybutelene to PEX adapter couplers. (Sharkbite connector was color coded so you know which side to use on which pipe)

 

[Deano2002]

Isaac, I'm not looking to replace what I have, I am going with all new pex-a or pex-b, my question is about which fittings to go with, crimp or expansion as I said

 

[Mark_K5LXP]

Lots of crimp done I'm sure and if done correctly I'm sure checks the box. Where I parted ways with crimp is you can't always get into a wall cavity, behind a fixture, in a mess of co-located pipes, what have you to make the ideal crimp. When I remodeled the S&B bathrooms I went with expansion and it was a breeze to do. No ungainly crimper, no wrestling it into position. Either a manual or power tool to expand it, then you've got some number of seconds to seat to the fitting, done. "Plug and play".

Mark B.
Albuquerque, NM

 

[Isaac-1]

Isaac, I'm not looking to replace what I have, I am going with all new pex-a or pex-b, my question is about which fittings to go with, crimp or expansion as I said

I personally like PEX-A and expansion fittings I see no upside to PEX-B other than it being slightly cheaper

 

[Sunnyfalls]

We replaced much of the crimp PEX-B in our 2 year old fiberglass Casita trailer with expansion PEX-A and ONLY use expansion PEX-A when doing domestic water plumbing and hydronic radiant floor heating projects. Expansion Tools and PEX-A are expensive but will never fail. Crimp tools and PEX-B are inexpensive and failures may occur...especially if the installer doesn't accomplish the crimps within specifications...which likely is an issue with RV manufacturing.

 

[Isaac-1]

You can get a manual expansion too for PEX A for around $100 online, though they are about the size of a pair of garden loppers, so take some free space to work. They also take a good bit of upper body strength to operate when using 3/4 inch couplers, and an insane amount for 1 inch. Though I suspect everything in an RV will be 1/2 inch, which is much easier

 

[Deano2002]

Fortunately we loan our Milwaukee expanders at work for our insulated pex so easy to get

 

[Deano2002]

I looked at the pex-a at home depot yesterday and noticed it was much more flexible than the pex-b I bought at Menards which is a Sioux brand product and has always been a reputable name. HD was made in China ( Apollo) and read some not so good reviews about it. Now I need to find pex-a somewhere else, I have all the expand fittings and the Uponor collars. Thanks all for the help!

 

[Deano2002]

after all this time I finished running all new pex A expanded fitting. I know have have been pressure testing and am loosing pressure from 80 psi to 60 in the morning. I have soaped every joint a few times and see no bubbles, pressurized the system through the water heater. I didn't isolate the water pump and wonder if that might be a problem, I have not soaped that yet. I guess the next thing to do is to fill with water and I will see water dripping.

 

[Isaac-1]

Pressure will drop when temperature drops, the less air space in the plumbing the greater the effect. Try checking after 24 hours when the temperature is stable, ie not after a cold front, etc.

 

[Kirk]

I guess the next thing to do is to fill with water and I will see water dripping.

When you do that, just wrap a dry paper towel around each connection and hold with a twist-tie or something similar. The towel will show it has seen water even if it should dry before you locate it and it will also keep any small drips from making a mess to clean up.

 

[Sunnyfalls]

Properly installed PEX expansion fittings using quality PEX-A won't ever fail or leak. Any system pressure loss is from another reason. We only use Uponor PEX and fittings for our domestic plumbing projects (AquaPEX for potable water) and for our hydronic radiant floor heating projects (hePEX with O2 barrier). We only get our PEX from SupplyHouse.com

https://www.borstengineeringconstruction.com/SupplyHouse.pdf

Gayle & Bob
"Los Gatos Casita"

 

[Deano2002]

We use Sioux Chief and Uponor at the company I work for and both have zero manufacturer problems, although I stayed away from Uponor's colored Pex A after I read the the documented issues they had, maybe it's been solved now, my leak was at a 90 degree fitting where I went from pex to nylon reinforced hose to the toilet, a little tightening on the hose clamp and no more leaking there, however my Dometic flush valve is leaking. Wondering if 80 psi of air pressure caused that anyway, new one is on the way. Thanks for the help all