To get email notification when someone adds to a thread you're following, click on the star in the thread's header and it will turn yellow; click again to turn it off. To edit your profile, click on the gear.
The Wall has a powerful search engine that will go all the way back to 2002. Use "quotation marks" around multiple-word searches. RIGHT-CLICK on the results and choose Open Link In New Window so you'll be able to get back to your results. Happy searching!
In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.

Pipe size to cast iron radiators

KendoKendo Posts: 3Member
Hey everyone! I have a job that i looked at today and the cast iron radiators are piped in 1/2 pex. Its piped in series from one radiator to another. No venturi tees. Does anyone think this system will work? And if not what is the best way to pipe it? Thanks in advance. Kenny


  • Alan (California Radiant) ForbesAlan (California Radiant) Forbes Posts: 937Member ✭✭
    You don't need

    venturi's on a series system.

    It may work as long as the radiators on the 1/2" PEX loop are less than 15,000 BTU output (total).

    Typically, the best way I like to pipe radiators is 2-pipe, indirect return.
    Often wrong, never in doubt.
  • kcoppkcopp Posts: 1,768Member ✭✭✭
    edited May 2014
    I am pretty....

    sure that will not work right.

    I looked at a similar system years ago and they were tring to do that w/ 3/4" pex....didn't work either.

    I ended up installing a set of manifolds (s&r) w/ 6 ports (for 6 rads)  and ran 1" to the manifold. 1/2" pex to each rad. I set the new boiler up w/ a outdoor reset control and the system worked very well.
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    Will it work?

    IMO, it will never work properly if it is as you describe. You can only run so many Gallons Per Hour of hot water through the radiators, the first radiator will get hot and the last one may never get hot. If it is piped as a series loop, like 3/4" copper baseboard. It was obviously installed by someone who had absolutely no understanding of how and why fluids travel through a hydronic system.
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    In & Out:

    Did you mean a two pipe reverse return?
  • KendoKendo Posts: 3Member
    Thanks for the input

    Thanks for the input.  I figured i was going to have to repipe it.  Just wanted to make sure.  Thanks alot
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!