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Hot water system piping

Dave8699
Dave8699 Member Posts: 53
in Gas Heating
So i have customer that would like to convert his 1 zone system to a 2 zone. The system has 14 cast iron radiators 7 on each floor with the feed and return going into the basement. My tought was running two 1" pex lines feeds and two 1" pex returns with tees to each radiator. My question is will the system work correctly and be balanced or will the first radiator on the main line be hotter then the last rad on the main line. I will attach a diagram of what I was thinking.


Comments

  • John Ruhnke
    John Ruhnke Member Posts: 939
    It might be cheaper to put in some thermostatic radiator valves on each radiator. Then you can leave the piping alone and every radiator becomes its own zone.
    I am the walking Deadman
    Hydronics Designer
    Hydronics is the most comfortable and energy efficient HVAC system.
  • Danny Scully
    Danny Scully Member Posts: 1,440
    edited September 2019
    Those thermostatic radiator valves, however, will not start and/or stop the boiler. This isn’t to say it’s a bad approach, but does it offer the result you desire? If you were to re-pipe it, I would suggest 2-pipe reverse return. This would address the potential balance issues you’re concerned with.
  • Dave8699
    Dave8699 Member Posts: 53
    I thought about the TRV but like Danny said, but I would not be able to turn on 1st floor from the 2 zone. So that would not be an option.

    Danny what do you mean by 2-pipe reverse return. I was thinking of running two 1 " feeds and two 1" returns 7 rads each.
  • Danny Scully
    Danny Scully Member Posts: 1,440
    Look up 2-pipe reverse return piping schematic. Essentially, the first radiator to be supplied with water is the last radiator to return water to the boiler.
  • Dave8699
    Dave8699 Member Posts: 53
    ok so thats the technical term so the schematic I posted is a 2- reverse return.
  • Danny Scully
    Danny Scully Member Posts: 1,440
    Yes, I apologize.
  • Dave8699
    Dave8699 Member Posts: 53
    No worries I appreciate the conformation, on another note I'm assuming that you use regular tees not monoflow tees?

    Also will 1" uponor hepex be big enough for the feed and return for 7 Rads which are all different pipe sizes 3/4 and 1".

    my plan is to have Two 1" feeds and two 1" returns back to the boiler with a 11/4" feed and return with a Alpha 2 pump .
  • Danny Scully
    Danny Scully Member Posts: 1,440
    What is the BTU load of the radiators?
  • Jamie Hall
    Jamie Hall Member Posts: 24,856
    Yes regular Ts
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Dave8699
    Dave8699 Member Posts: 53
    Thanks to everyone who helped out, next visit ill measure rads and come up with a EDR and ill post them.

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