Don't use cellular core PVC for venting

Discussion in 'Tankless Water Heater Forum' started by cecil1966, Sep 30, 2017.

  1. cecil1966

    cecil1966 New Member

    Joined:
    Aug 29, 2017
    Location:
    SC
    I didn't know there were two kinds of Schedule 40 PVC. The wording to me seemed like cell core was something different than Sch 40, and was so eager to install didn't catch it. I decided to relocate WH to an outside utility room after learning that this WH also had an on board heater to prevent freezing. Just keeping a light on in this room will prevent freezing but that's why I decided to put it inside originally. The venting was also much easier outside with a vent terminal that's much better than two pipes sicking out the wall. I used PEX this time with curved corner braces and I can't notice any reduction in flow from the all copper set up. Both ran 2 showers and 2 faucets, maybe could do more but that was the extent of my testing for both installs. I read so many post about this heater and many others I'm surprised no one mentioned the specific PVC. Rheem water heater has been flawless though. Pleased with it now and learned a lot as that can be part of the process for first go around with something new.
     

    Attached Files:

  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Joined:
    Jan 5, 2008
    Occupation:
    Test, Don't Guess!
    Location:
    Land of Cheese
    Pretty common knowledge in the trades. Solid core is getting harder to find in some of the big-box retailers.
     
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. cecil1966

    cecil1966 New Member

    Joined:
    Aug 29, 2017
    Location:
    SC
    I didn't claim to be in the pluming trade and said this was first tankless install. I posted this for DIY, maybe avoid the mistake. Directions could have been more clear. HD and Lowes doesn't stock solid core Schedule 40 in 3'' or 4''.
     
  5. Master Plumber Mark

    Master Plumber Mark Sensitivity trainer and plumber of mens souls

    Joined:
    Feb 6, 2005
    Occupation:
    Sensitivity trainer.. plumber of mens souls
    Location:
    indianapolis indiana - land of the free, home of
    Something else you are not supposed to do is run galvanized pipe for your gas supply,,,
    it is supposed to be black steel pipe for gas lines because the zinc coating can flake off the
    galvanized pipe and clog up the gas control in the unit......

    this is common in most parts of
    the USA and normally will get the job red tagged if the gas guy sees the galv piping for gas
    Very few areas of the country will let you use galvanized pipe on gas lines....

    ...
     
  6. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Listen to the master!

    That is just one of several reasons why some states don't allow anybody but licensed gas fitters to work on residential gas plumbing.
     
    Sylvan likes this.
  7. cecil1966

    cecil1966 New Member

    Joined:
    Aug 29, 2017
    Location:
    SC
    All the gas lines here from the meter are galvanized. The gas company came by and inspected the meter and galv gas lines, no problem. I did some research and you can use either. Mark, aren't you the one who hates tankless heaters? And tells everyone how terrable they are? Last plumber charged my mom $1200 to switch out her tank WH and sounded a lot like you.

    Did you not see the sediment trap? I don't think I could get a plumber to run a hard line to the WH. Too much work.
     
    Last edited: Oct 4, 2017
  8. cecil1966

    cecil1966 New Member

    Joined:
    Aug 29, 2017
    Location:
    SC
    The galvanized vs black has been beat to death on many many forums. Just like tankless heaters it depeneds on where region you live in. In areas that have a lot of salt air from the ocean (I live on the ocean) galvanized is used. I talked to one plumber who threads his own pipe and he reccomeneded galvanized here and said he has seen black pipe rust out in the crawl space in front of a vent, where the salt air blows through. I would have used him if I had the funds but having to do a lot of this myself this time around. Sorry I posted. I'll find another forum with people who are more friendly and helpful. You pros should stick to gouging old ladies switching out tank water heaters. Make sure to keep some shark bites on the truck incase you need to fix a leak.
     
  9. Master Plumber Mark

    Master Plumber Mark Sensitivity trainer and plumber of mens souls

    Joined:
    Feb 6, 2005
    Occupation:
    Sensitivity trainer.. plumber of mens souls
    Location:
    indianapolis indiana - land of the free, home of

    My, my ... I sure twisted your tail out of joint over this tankless install of yours...
    everything else looks pretty average to me.....

    Black gas pipe is normally is what is used in the mid west... It all really depends on where you are located in the USA....
    in our area its best to use black pipe.... other parts of the USA it is ok....
    Foam core pipe is not supposed to be used but I have seen a lot of that in service on power vented water heaters for a long time now..... I would not worry about it too much.....

    I am sorry if this very minor critique of your tankless heater has hurt your feelings, got you all upset , and made you cry.


    if you cant take criticism, dont blame me or get all upset with this forum ... just because you have tender feelings, you should not be taking this personally...
    and also then perhaps you should not be posting pictures of your work......

    now you go make yourself a hot co-co and snuggle up under some blankets
    with a heating pad and a good book, you will feel better about it all in the morning.....
     
    Sylvan likes this.
  10. StyleandgraceOrSlapngo ?

    StyleandgraceOrSlapngo ? New Member

    Joined:
    Apr 13, 2019
    Location:
    Los Altos Hills, Ca
    yes , we shouldn't pick each other s photos apart like bullies .... I think a lot of DIY projects come out well despite their first time. I've taken apart galv gas lines , no pitting or flaking to concern with ....nuances and minutia can be argued to death.... what good does it do? throw out an atta boy on the points you find splendid... try it !!
    Genny

    for laughs and giggles, Also I included a pic from the Rheem 140 k btu indoor unit I installed yesterday, you can critique it. , I won't get them in a bunch or. take a long hot bath and pout....
    Ohh and I haven't put on the condensate tube to the 3/4 pvc yet ... and the pic cut off too high - doesn't show the 2 hole strapping securing the vertical piping. how d I do ?
     

    Attached Files:

    Last edited: Apr 13, 2019
  11. Master Plumber Mark

    Master Plumber Mark Sensitivity trainer and plumber of mens souls

    Joined:
    Feb 6, 2005
    Occupation:
    Sensitivity trainer.. plumber of mens souls
    Location:
    indianapolis indiana - land of the free, home of
    it looks about average to me....

    I am pretty sure that your gas line is too small for it to work properly
    you might want to check the specs on it... Running too small a gas line
    is what usually is the problem with most of them ...It should be at least
    a full 3/4 coming off a one inch line.....

    I have been thinking of installing a navian in my house off a one inch
    line nearby just to see how I like them but have not gotten around to it...
    Gonna wait until my 75 gal bradford finally fails then maybe ...
    I dont need the marital issues if she dont like how it works..
     
    Sylvan likes this.
  12. Sylvan

    Sylvan Still learning

    Joined:
    Sep 23, 2004
    Occupation:
    plumbing- - fire suppression
    Location:
    New York
    "Something else you are not supposed to do is run galvanized pipe for your gas supply,,,
    it is supposed to be black steel pipe for gas lines because the zinc coating can flake off the
    galvanized pipe and clog up the gas control in the unit...... "

    I used to believe that galvanized was not permitted on natural gas lines for the following reasons

    1- Zinc can hide a defect in a fitting

    2- Brass gas valves will has an electrolytic action with galvanized

    3- Zinc coating can cause restriction of flow if it peels <<< all of the above are untrue

    I had to run 3" gas piping to roof units and rather then having to paint black steel I opted for galvanized and also use galvanized when there is excessive moisture present . Never failed any inspection

    403.8 Protective Coating

    Where in contact with material or atmosphere exerting a corrosive action, metallic piping and fittings coated with a corrosion-resistant material shall be used

    404.9 Protection Against Corrosion

    Metallic pipe exposed to corrosive action, such as soil condition or moisture, shall be protected in an approved manner. Zinc coatings (galvanizing) shall not be deemed adequate protection for gas piping underground. Ferrous metal exposed in exterior locations shall be protected from corrosion. Zinc coatings (galvanizing) shall be deemed adequate protection for gas piping exposed in exterior locations. Where dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders.
     
  13. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    If you can get the gas company to increase your pressure to 2 psi instead of 1/4 psi, you can have lots and lots of BTUs through the existing pipe. Even feed that whole house generator you were thinking about.
    https://www.citizensenergygroup.com...ncrease-Natural-Gas-Pressure-or-Add-Equipment

    Wait... are you joking about the tankless maybe??? I didn't think you would go that way.
     

Share This Page