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Zone valve versus circulators, updating a system

brxlbrxl Member Posts: 8
edited December 2017 in Controls
Hello everybody, I am new here and already spent some time reading through the forums.
Our infloor heating has 9 loops, 1-4 for 4 separate rooms and 5-9 is the main living area. For money reasons we had it installed with one circulator pump and one thermostat (in the main area). The bug bite me and I ordered 2 Rehau actuators (zone valves), a Taco 5 zone controller and I am happy to report that now it runs really nicely controlling two of the rooms individually. (I need to brag here...first time I did an install on a heating system...and it worked right away!). there are two paths to complete the system

A) buy the rest of the actuators to a total of 9 (at $45), install and probably a relay bank and additional transformer would be advisable as the main zone consists of 5 ZVs

B) reengineer the manifold, in which the 4 separate rooms get their ZVs, but alter the plumbing for loops 5-9 with a dedicated pump (there is an output on the Taco to switch primary and secondary pumps already and currently unused), thus saving on ZVs, but buying a 4 loop and reusing 5 of the current 9 loop manifolds, plus misc. parts, the pump...lots of time and much more opportunity for things to go wrong (i.e. drain the glycol mix, purging) than just slapping on components as in A.

I would love to hear your take on this, what would be your considerations?

A general question...the current pump is a Grundfos 26-99. When a single zone comes up isn't the flow rate "mismatched" compared to driving all 9 loops like before?



  • NY_RobNY_Rob Member Posts: 1,370
    How about a simple drawing of your current layout?
  • brxlbrxl Member Posts: 8
    edited November 2017

    Manifold (MF), loop 1 to 4 goes to rooms 1 to 4, each 200sqf
    loop 5-9 go to main room, 900 sqf

    9 loop manifold, fitted with ZVs on loop 2 and loop 3, this would be where the separation between ZVs and 2nd circulator would need to happen.
  • Leon82Leon82 Member Posts: 684
    A Delta p circ will adjust automatically as zone valves turn on and off.
    Like the alpha or 1816, as long as they can handle the full load.
  • brxlbrxl Member Posts: 8
    I haven't figured out how to post pictures here, but check my avatar for it ;-)
  • NY_RobNY_Rob Member Posts: 1,370
    If you posted drawings... they didn't show up.
  • brxlbrxl Member Posts: 8

    Manifold (MF), loop 1 to 4 goes to rooms 1 to 4, each 200sqf
    loop 5-9 go to main room, 900 sqf
  • brxlbrxl Member Posts: 8
    ha! and suddenly it works well with the drag and drop, here the 9 loop manifold with the current 2 ZVs hooked up

  • ZmanZman Member Posts: 6,322
    It is a bit unconventional but I would just buy the actuators and put one on each loop.
    The 26-99 is way big for you system, especially with just one zone calling. It would recommend the grundfos alpha set to cp2
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • brxlbrxl Member Posts: 8
    Thanks for the recommendation. I like the setup of the Alpha.
    Since 5 valves would be called at the same time for the main zone, I'd better look at some 24V 10A relay and beefy transformer to feed those ZVs ;-)
  • NY_RobNY_Rob Member Posts: 1,370
    If you're going with an ECM pump, install a "dirtmag" or make sure you get the Alpha II vs. the original Alpha.
  • jumperjumper Member Posts: 1,568
    What the world needs now is teeny weenie pumps for each zone. Nuts to zone valves.
  • hot_rodhot_rod Member Posts: 14,397
    Caleffi and some others offer low current draw thermal actuators now, 250 Ma. You should be able to run 7 or so on a 40va transformer. They only draw full current for a few seconds then the taper off the draw.

    The Caleffi TwisTop 6563 is now available in a low current draw version, A very popular actuator

    The Caleffi 6 zone ZVR has two 40 va transformers onboard.

    What brand manifolds. I’d need to confirm that our actuators fit and stroke properly.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • brxlbrxl Member Posts: 8
    Wow, this is lots of excellent info. Keep them coming, the manifold is Rehau

  • brxlbrxl Member Posts: 8
    I did find the 656304's current at that's 19.2 VA each. Since zone 5 (a fraction of the all the others) is a joke...I will try to run 4 zones for the main initially. The Taco also has 2 40VA just gotta make sure they are not all calling at the same time.
    Anyway, from the first look they may use the same treading, can't find about the stroke 656304 versus Rehau 260166.
    Would you expect them to have different strokes?

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