PEX-A Design Questions

[Rhettccampbell]

I am looking for some assistance with the my Pex plan for an upcoming remodel. I have included my sketch plan, based on research for the best system(s), however, there appears to be a fair amount of debate with regard to the best system/method to use. I am hoping someone would be willing to provide some input (even if I am on the wrong track completely). Currently, the plumbing is approximately 35 years old and is copper buried in the slab, which has led to a few leaks recently. The house is in Southwest Florida, so Pex can feasibly (and legally) be ran through the attic. While I have done plumbing projects over the years, I have never designed a system and I cannot afford an engineer to draw the plans up.

I have never been a fan of wasting water, therefore I wanted to stay away from the trunk and branch system, and instead I wanted to put a recirculation system that is either ran with a timer, or an Aquastat flow sensor.

This setup includes a mainline coming in from the left side of the house. I plan to loop the hot line with 3/4" loop with hot with reducing Tee's to 1/2" to each fixture, with the exception of the Master Bathroom Dual-Sink Vanity, where I’ll branch off the first connection. A spring-loaded check valve will e placed before re-entering the cold line and another spring-loaded check valve will be placed between the incoming water and the water heater.

The cold line would be a similar setup with regard to distribution to the fixtures. A separate line will run to the exterior hose bibs, with an in-line spring loaded check valve before the 1st branch. I plan to use the Wisbro Uponor Pex A, ProPex Expansion joint system with Brass Fittings.

My questions are:

• Where is best place to place the recirculating pump?
• Will this supply enough hot water to run multiple fixtures at once ( i.e. both showers while the dishwasher or washing machine are running)?
• Are my check valves locations in the correct locations? And do you still recommend vacuum breakers on each of the hose bibs?
• Lastly, since I will be removing a lot of the sheetrock in the areas where the hose bibs currently are (or will be) I plan to run the Pex down the interior side and then through the cylinder block wall. Frost proof is not necessarily needed (and seemingly an unnecessary expense). Do I run larger diameter pvc (or similar) through the wall, and then run PEX through the pipe and seal with caulking? Or is there a better alternative?

Thank you for taking the time to consider my project and I appreciate any feedback.

 

[hdtvkeith]

I have no experience other than I am about to repipe my own home. When I chatted with several plumbers that came out to quote my job the common theme I heard was most of them recommended Pex-b because they had seen premature Pex-a failures especially in hot water lines and recirc setups. Again this is third party info. I also suspect it was also because of the now issues with the colored pex pipes. I do not have hot water recirc, and I am going Pex-a mostly because I don’t want to go through the upsize exercise with Pex-b, but I gathered Pex-b may be more tolerant of the constant hot water in the pipes.

 

[Twowaxhack]

I’ve been using rehau pex for years without a single pipe leak.

crimp fittings with copper crimp rings.

Our water ph is around 7.5.

If I put pex in my house that’s what I’d use. End of story

 

[hdtvkeith]

I am wondering what is considered a high chlorine level in water to be concerned. I am looking at my municipality water report from 2021 and they don’t list PH, but they list chlorine levels of 2.1 ppm and chlorite at .40 which if I am reading their report is at the max of the range.

 

[Twowaxhack]

I am wondering what is considered a high chlorine level in water to be concerned. I am looking at my municipality water report from 2021 and they don’t list PH, but they list chlorine levels of 2.1 ppm and chlorite at .40 which if I am reading their report is at the max of the range.

Check it at your tap, they’re giving you the analysis of the water when it leaves the treatment plant.

 

[hdtvkeith]

Yeah I was thinking it need to get my water tested especially after all the pinhole leaks, which the water company swears (via numerous studies) that it is not their water.

 

[Twowaxhack]

Pinholes are often caused by low ph. Acid water.

 

[hdtvkeith]

Yeah there is some cpntroversy in my area about the water vs. was it poor install sin the 80s.

 

[Twowaxhack]

Yeah there is some cpntroversy in my area about the water vs. was it poor install sin the 80s.

It was/is the water.

Flux corrosion doesn’t occur in long straight runs. Typically it’s near fittings or below fittings where the flux ran down.

How would a poor install cause pinhole leaks everywhere ? It’s not undersized.

 

[hdtvkeith]

Yeah I know. They had 2 or 3 studies done that said i was not the water, but everyone around here says BS. I also found it odd the the pihole leak (5 of them) all were on horizontal, 4 were midway in decently long sectiona dna all were in the top half of the pipe.

 

[Twowaxhack]

Yeah I know. They had 2 or 3 studies done that said i was not the water, but everyone around here says BS. I also found it odd the the pihole leak (5 of them) all were on horizontal, 4 were midway in decently long sectiona dna all were in the top half of the pipe.

the water or cheap foreign copper pipe. That’s my belief.

Was the home ever on well water ?

 

[hdtvkeith]

It is county water system, but I suspect it was foreign pipe and the water. The county did admit to some areas where chlorine levels may have been too low for a period, without really admitting it was them. The 1984 time frame was I believe that period of cheap copper pipes. Either way I am ripping it all out for Pex. Most of the prep is done, all, walls and ceilings open and pipe comes Tuesday. I did 2 sticks of L copper to do the water heater and expansion tank section.