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 01-08-2012, 02:27 PM   #1
Newbie
 
Join Date: Jan 2012
Posts: 1
Rewards Points: 10
Default

Pipe sizing from copper to pex.


I am installing a new shower system (3/4") - the main is 3/4" but splits immediately into 1/2" cold and 1/2" to the hot water heater. I'm thinking I need to re-plumb all the way back to the 3/4" copper main.

The question is should I go with 1" pex, or 3/4" pex. I know it's counter intuitive to go from 3/4" copper main to 1" pex, but I thought I read somewhere that pex actually has a smaller inside diameter and a lower flow rate. I'm thinking by going 1" pex down the center of the house (where everything feeds from), I won't have water pressure issues later on. I'll tee off all the old feeds into the 1/2" existing copper.

The shower will have a rain shower, two hand helds and 4 body wash jets - so will pull quite a bit of water) although likely they will not all be on at the same time).

Any thoughts?

rmachon is offline   Reply With Quote
Old 01-08-2012, 02:58 PM   #2
Civil Engineer
 
Join Date: Mar 2009
Location: Boston
Posts: 4,252
Rewards Points: 2,082
Default

Pipe sizing from copper to pex.


PEX is slightly less rough than copper, therefore the difference in inside diameter typically makes little or no difference to effective flow rate. You can use 3/4 inch PEX or 3/4 inch copper, makes no difference to the total flow.

Daniel Holzman is offline   Reply With Quote
The Following User Says Thank You to Daniel Holzman For This Useful Post:
rmachon (01-09-2012)
Old 01-08-2012, 03:02 PM   #3
MarginallyQualified
 
Join Date: Dec 2011
Location: Winston-Salem NC
Posts: 3,681
Rewards Points: 2,036
Default

Pipe sizing from copper to pex.


Quote:
Originally Posted by rmachon View Post
I know it's counter intuitive to go from 3/4" copper main to 1" pex, but...

...the main is 3/4" but splits immediately into 1/2" cold and 1/2" to the hot water heater. I'm thinking I need to re-plumb all the way back to the 3/4" copper main.
If you have 3/4" copper water service then you should maintain that throughout the house (as the primary material and size) including into and out of the water heater.

When you get to fitting tees for the several fixture you can reduce to 1/2" for most.

Quote:
I am installing a new shower system...
The shower will have a rain shower, two hand helds and 4 body wash jets - so will pull quite a bit of water... Any thoughts?
Mostly that it seems a silly and wasteful indulgence. As to the plumbing work needed... whatever size fittings the MIXING VALVE calls for is what I'd connect to it.

hth

Last edited by TarheelTerp; 01-08-2012 at 03:05 PM.
TarheelTerp is offline   Reply With Quote
The Following User Says Thank You to TarheelTerp For This Useful Post:
rmachon (01-09-2012)
Reply

Tags
flow rate, pex, pex to copper


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
PVC air admittance value and copper waste pipe diy888 Plumbing 2 02-16-2011 07:48 AM
Copper to Black Pipe Gas Connection dwolek HVAC 1 03-15-2010 05:02 PM
Connect 2" pvc drain to 2" copper pipe - no subfloor access missfixer General DIY Discussions 3 09-05-2009 05:44 PM
sizing gas pipe SNC Plumbing 3 12-10-2008 07:33 PM
copper strap around copper pipe? analogmusicman Plumbing 3 06-04-2008 10:55 AM




Top of Page | View New Posts

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