Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 06-17-2008, 06:05 AM   #1
Member
 
Join Date: Jan 2008
Posts: 179
Share |
Default

Is 1/2 Pex more restrictive than 1/2 copper?


I have read on this site that Pex is restrictive. Can anyone explain why 1/2 Pex is more restrictive than 1/2 copper? I would think Pex would be less restrictive due to being very smooth. Any info would be appreciated.

twilightcall is offline   Reply With Quote
Old 06-17-2008, 06:18 AM   #2
Member
 
Join Date: Oct 2006
Location: Hermitage Pa.
Posts: 586
Default

Is 1/2 Pex more restrictive than 1/2 copper?


what do you mean by restrictive? I have Pex through out my house with no problem what so ever

clasact is offline   Reply With Quote
Old 06-17-2008, 08:01 AM   #3
Member
 
RippySkippy's Avatar
 
Join Date: Feb 2007
Location: Ames, Iowa
Posts: 1,233
Default

Is 1/2 Pex more restrictive than 1/2 copper?


With out researching it throughly, I'm guessing the reference comes from the fact that the Pex fitting fits inside the pipe, therefor you have a much smaller diameter for water to flow as it passes through fittings.

My house has Pex with a manifold and home run system...and it's not caused any problems whatsoever. The only place I up-sized was for the 90 gal bubble tub, it's run at 3/4" with high flow fixtures. Most residential installations won't see a problem if they there is adequate pressure and flow to the house to begin with, of course that's just my take.
__________________
when it comes to breakfast, the chicken is dedicated, the pig is committed.
LMASD
RippySkippy is offline   Reply With Quote
Old 06-17-2008, 09:12 AM   #4
Doing it myself
 
Alan's Avatar
 
Join Date: Apr 2006
Location: Crescent City, CA
Posts: 3,738
Send a message via AIM to Alan Send a message via MSN to Alan
Default

Is 1/2 Pex more restrictive than 1/2 copper?


if you're talking about my post about using pex for a tub spout, i'm referring to the inside diameter of the fitting, which is closer to 3/8"

The pipe is the same diameter, but copper fittings go on the outside, and the pex fittings go on the inside.
__________________
Journeyman Plumber
Alan is offline   Reply With Quote
Old 06-17-2008, 10:16 AM   #5
Member
 
Join Date: Oct 2006
Location: Hermitage Pa.
Posts: 586
Default

Is 1/2 Pex more restrictive than 1/2 copper?


Ok now this depens on where you live because some places have code against this.I ran a system like RippySkippy,off a manifold I ran 3/4 pex but use shark bite fitting instead of the crimp type.The fitting fit over the outside so no reduction of size but like I said they are not code in all places.If you are allowed to use them they are a bit on the high end of price but for time saveings and ease and reusability they cant be beat.I have had them for over two years now and no leak or problems at all and I have had to reconfigure a couple of lines due to differant renovations.They do make them with shut offs and thread type for attaching supply lines to and reduction type also.I have had no reduction in water presure as a matter of fact I saw an increase once it was all set up.As I stated though if codes apply check to see if you can use them first.Some may not agree with how I ran mine but it works great for me.
clasact is offline   Reply With Quote
Old 06-17-2008, 12:44 PM   #6
Member
 
Join Date: Jan 2008
Posts: 179
Default

Is 1/2 Pex more restrictive than 1/2 copper?


Thanks guys. I appreciate the info. I was referring to the pex fittings. They get fairly narrow and the copper fittings go on the outside so I just wanted to know if anyone has had problems with the water flow due to the fittings etc.
twilightcall is offline   Reply With Quote
Old 06-17-2008, 04:01 PM   #7
Registered User
 
Termite's Avatar
 
Join Date: Apr 2008
Posts: 6,520
Default

Is 1/2 Pex more restrictive than 1/2 copper?


It'll vary depending on system setup, flow, and pressure. Most 1/2" pex fittings neck down to 3/8" at the fitting. There are systems that expand the pex to fit over an actual 1/2" fitting, but they're less common and the tools are expensive.

I ran regular Zurn/QuestPex 1/2" in my house to every fixture, with the fittings that neck down to 3/8". I replaced a 1/2" copper system. I saw no reduction in flow or pressure at all. The sinks and showers work the same, and the toilet fills just as fast.
Termite is offline   Reply With Quote
Old 06-17-2008, 09:44 PM   #8
Doing it myself
 
Alan's Avatar
 
Join Date: Apr 2006
Location: Crescent City, CA
Posts: 3,738
Send a message via AIM to Alan Send a message via MSN to Alan
Default

Is 1/2 Pex more restrictive than 1/2 copper?


Quote:
Originally Posted by thekctermite View Post
It'll vary depending on system setup, flow, and pressure. Most 1/2" pex fittings neck down to 3/8" at the fitting. There are systems that expand the pex to fit over an actual 1/2" fitting, but they're less common and the tools are expensive.

I ran regular Zurn/QuestPex 1/2" in my house to every fixture, with the fittings that neck down to 3/8". I replaced a 1/2" copper system. I saw no reduction in flow or pressure at all. The sinks and showers work the same, and the toilet fills just as fast.
Even if you try to use all the fixtures in the bathroom at once?
__________________
Journeyman Plumber
Alan is offline   Reply With Quote
Old 06-17-2008, 10:21 PM   #9
Registered User
 
Termite's Avatar
 
Join Date: Apr 2008
Posts: 6,520
Default

Is 1/2 Pex more restrictive than 1/2 copper?


We've used the sink and the shower at the same time with no noticeable drop. I'm sure there's a difference, but you gotta be more observant than me to notice it.
Termite is offline   Reply With Quote
Old 06-17-2008, 11:39 PM   #10
Doing it myself
 
Alan's Avatar
 
Join Date: Apr 2006
Location: Crescent City, CA
Posts: 3,738
Send a message via AIM to Alan Send a message via MSN to Alan
Default

Is 1/2 Pex more restrictive than 1/2 copper?


Well, just for the sake of argument, you'll probably never, or rarely use all of those fixtures at once, but I just repiped my house in pex, and I turned the tub spout on full bore cold, turned the lav wide open cold, and flushed the toilet, and it was definitely noticeable...... still useable? Yes.

But if you like to put out fires while you take a shower......
__________________
Journeyman Plumber
Alan is offline   Reply With Quote
Old 06-18-2008, 07:59 AM   #11
Member
 
RippySkippy's Avatar
 
Join Date: Feb 2007
Location: Ames, Iowa
Posts: 1,233
Default

Is 1/2 Pex more restrictive than 1/2 copper?


For the reasons mentioned regarding pressure/flow drop, that's why I like manifolds and home runs. While it may not eliminate all flow/pressure issues, it certainly can't hurt when you have a 3/4 inlet and 1/2 out, in theory, the impact should be minimal. Not saying it's right, just know it works.
__________________
when it comes to breakfast, the chicken is dedicated, the pig is committed.
LMASD
RippySkippy is offline   Reply With Quote
Old 06-18-2008, 08:46 AM   #12
Registered User
 
Termite's Avatar
 
Join Date: Apr 2008
Posts: 6,520
Default

Is 1/2 Pex more restrictive than 1/2 copper?


Quote:
Originally Posted by RippySkippy View Post
For the reasons mentioned regarding pressure/flow drop, that's why I like manifolds and home runs. While it may not eliminate all flow/pressure issues, it certainly can't hurt when you have a 3/4 inlet and 1/2 out, in theory, the impact should be minimal. Not saying it's right, just know it works.
Absolutely. I'm on board with running as many lines as possible off a larger manifold setup. That is definately the best installation. There are so many variables in play...What works well in one house will work differently in another.
Termite is offline   Reply With Quote
Old 06-20-2008, 10:24 AM   #13
Newbie
 
Join Date: Jun 2008
Posts: 3
Default

Is 1/2 Pex more restrictive than 1/2 copper?


pex has known to have failures when in direct contact with sunlight and extreme temperatures of hot water running through it.
bazmanblue is offline   Reply With Quote
Old 06-20-2008, 11:22 AM   #14
Member
 
RippySkippy's Avatar
 
Join Date: Feb 2007
Location: Ames, Iowa
Posts: 1,233
Default

Is 1/2 Pex more restrictive than 1/2 copper?


Quote:
Originally Posted by bazmanblue View Post
pex has known to have failures when in direct contact with sunlight and extreme temperatures of hot water running through it.
You are right, but there's more to what you're implying.

Wirsbo, now Uponor, plumbing specs say to avoid sunlight exposure to 30 days and the temperature/pressure chart is:
200F (93C) at 80 psi (551 kPa)
180F (82C) at 100 psi (689 kPa)
73.4F (23C) at 160 psi (1,102 kPa)
So yes there are limitations, and as DIY'ers we all should be aware of a specific product limitations and know what we are dealing with. In our living situation all pipes are protected from sunlight, so that's not an issue, and our pressures are well below those stated.
__________________
when it comes to breakfast, the chicken is dedicated, the pig is committed.
LMASD
RippySkippy is offline   Reply With Quote
Old 06-20-2008, 11:45 PM   #15
Licensed Master Plumber
 
mstplumber's Avatar
 
Join Date: May 2008
Location: Atlanta, GA USA
Posts: 211
Default

Is 1/2 Pex more restrictive than 1/2 copper?


For what it's worth:

Although most PEX manufacturers really push manifold systems, could that be because a manifold system uses a lot more pipe?

While a manifold system may be an acceptable choice in some applications, there are several factors which need to be considered. Manifold systems often waste water. This is because of the need to clear the cooled water out of hot water lines when you want hot water. When the hot water has not been used for a while the water in the pipes cools down (unless you have a circulating system of some kind). In order to get hot water, most people just let the cooled water run down the drain until it heats up. With a standard, "non manifold" system this usually only has to be done once at each bathroom group. With a manifold system each fixture has to have it's supply purged of cooled water separately. Even though the individual lines are usually 1/2" instead of 3/4", if you do the math you will see that that is more water wasted, especially if 2 people are using separate faucets in addition to the shower.

Another drawback of a manifold system is that you can't effectively install a circulation system if one is needed. This shortcoming again can contribute to wasted water going down the drain. Since water conservation is an increasing concern, this needs to be considered when choosing a water distribution design.

Cost is another factor. Manifold systems simply cost more due to the increased material requirements.

I know I'm going across the grain here and that there are thousands of houses out there with manifold systems. They certainly minimize the possible leak points in a piping system. They are not, however, for every application. They are also just not very "green". They use more material and contribute to less overall water and energy efficiency in the home.

__________________
Mstplumber

Check out my goofy video for my new toilet repair book.

Last edited by mstplumber; 06-20-2008 at 11:45 PM. Reason: typo
mstplumber is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
PEX vs. Copper Aglease Plumbing 41 02-16-2010 05:14 AM
Flexible copper or Rigid Copper for solar? Piedmont HVAC 5 06-11-2008 09:47 PM
Flexible Copper or Rigid Copper? Piedmont Plumbing 1 06-10-2008 01:40 PM
copper strap around copper pipe? analogmusicman Plumbing 3 06-04-2008 10:55 AM
Copper Hot Water Tank - Green Stain grover432 Plumbing 2 11-28-2005 11:05 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.