(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 2 of 2

Thread: Condensing Tankless Water Heater Venting Material (ABS, PVC, or CPVC)

  1. #1
    DIY Junior Member janderson13's Avatar
    Join Date
    Sep 2013
    Spokane, Wa

    Default Condensing Tankless Water Heater Venting Material (ABS, PVC, or CPVC)


    I plan to install a Takagi tankless heater http://www.takagi.com/download/produ...ion-Manual.pdf

    I'm confused as to what piping I should be using. I was planning to use ABS as the manual says that is ok as long as it can withstand 149 degrees F, is NOT foam core, and is ASTM D2661 compliant. I look at Home Depot and Lowes and they carry Charlotte ABS cellular core pipe (appears to be foam core), they say it has a heat rating of like 160 degrees F, and conforms to ASTM D2661. I realize that this appears to be foam core. I look at Charlotte's site and it says the pipe is only rated for 140 degrees F and is infact foam core, but that it is designed for venting applications.

    So... I look at my furance venting that is done in ABS and it is using the same Charlotte ABS cellular core pipe - I'm starting to wonder if this is dangerous now? Or does the furnace allow for a lower specification of pipe?

    I thought I would look for CPVC and they don't seem to carry that. I'll try Furgeson on Monday for the CPVP.

    I'm wondering what other people are using and if I should replace my furnace pipe. The time to do it is now because we are finishing our basement.



  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    New England


    The issue is how it reacts when it does get hot...a solid core product typically will stay firmer and not distort or sag (as much). The horizontal runs do need to be supported properly, and that helps minimize any issues. The existing pipe should have some markings on it which would allow you to verify if it is proper. If not, yes, I'd replace it while you have it open.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

Similar Threads

  1. Proper Venting of Rheem Condensing tankless water heater
    By Killer95Stang in forum Tankless Water Heater Forum
    Replies: 19
    Last Post: 04-13-2012, 12:04 PM
  2. Rheem condensing water heater with PVC concentric vent termination kit?
    By Killer95Stang in forum Tankless Water Heater Forum
    Replies: 0
    Last Post: 03-25-2012, 05:43 AM
  3. Boiler Decision: Oil or Natural Gas? 80%? 90%? Condensing? Tankless?
    By in.need.of.help in forum HVAC Heating & Cooling
    Replies: 19
    Last Post: 03-02-2012, 09:04 AM
  4. Paloma PHH-32DV condensing Tankless water heater installation
    By saphman in forum Tankless Water Heater Forum
    Replies: 2
    Last Post: 01-19-2012, 05:19 PM
  5. PVC venting for tankless water heater
    By RinconVTR in forum Tankless Water Heater Forum
    Replies: 4
    Last Post: 11-12-2010, 06:36 AM


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts