Replacing Cast Iron With PEX-Al-PEX - Plumbing - DIY Home Improvement | DIYChatroom

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


Thread Tools Display Modes
Old 02-07-2012, 10:17 AM   #1
Join Date: Jul 2011
Posts: 8
Rewards Points: 10

Replacing cast iron with PEX-Al-PEX

I am looking to change out all of the original cast iron pipe on the heat distribution system in a 100+ year old 3-story building that I am renovating in Easton, PA. The distribution system is on two NG boilers with feed pumps (1 for 1st floor; 1 for 2nd/3rd floors). The house was not properly winterized by the previous owners and several pipes and fittings burst. I saw a video on This Old House (you can view here) where they reconfigured a hot water radiator heating system with PEX-Al-PEX off of a manifold. If running the PEX-Al-PEX in this "home run" design, what size tubing would be required with dedicated supply/return to each radiator? I know there are practical requirements for flow and pressure, so I am wondering how small I can go on the ID. Can I get away with 1/2"? 5/8"? Or would I have to go all the way up to 3/4"? I would prefer a smaller diameter over a larger to reduce some of the costs, but not if it means installing an inadequate distribution system.

Thanks for your help!


Last edited by silvajus; 02-07-2012 at 10:40 AM.
silvajus is offline   Reply With Quote

heating , hot water heat , pex-al-pex , radiator

Thread Tools
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
replacing cast iron pipe davemarz Plumbing 1 05-20-2011 09:16 PM
replacing parts of cast iron vent stack amakarevic Plumbing 7 03-30-2011 03:41 AM
Replacing cast iron with PVC erm213 Plumbing 2 06-09-2010 09:38 PM
Replacing a Cast Iron Waste Pipe Beylah Building & Construction 0 01-18-2010 02:42 PM
working with cast iron ericadami Plumbing 9 11-30-2008 12:45 PM

Top of Page | View New Posts