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Radiant heating pump relay

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jamespet
jamespet Member Posts: 14
in Radiant Heating

I currently have this setup in my home. the pump circled runs when ever the main circulator pump is running. It does not effect much as long as the zone values are not open. I'd like to set it up to only run when one of the heating zone is calling. Just looking to add a bit more efficiency to the system. I have 2 Taco 404 EXP control units. Is there an easy way to do this or am I looking at adding in a relay to each zone with a unified output that will allow the pump to turn on. In a sense that is what I need to do, but is there a functionality in the Taco that will do this without modification.

CurrentSetup.png

Comments

  • hot_rod
    hot_rod Member Posts: 25,245

    Actuators with end switches on each manifold port would give you complete control. If multiple loops go to one zone, connect thje actuators to one t-stat.

    You need a ZVC control and actuators for the manifold

    Screenshot 2025-06-26 at 3.38.37 PM.png Screenshot 2025-06-26 at 3.40.23 PM.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • jamespet
    jamespet Member Posts: 14
    https://forum.heatinghelp.com/discussion/comment/1858780#Comment_1858780

    My system already has vales for each heating zone. The issue I have is that the pump for the heating zones runs when anything including just the DHW is running. I'd prefer that the radiant pump does not run when the furnace is just trying to heat hot water. I am trying to find a way to isolate that pump. Its an older system and the pump is not pressure regulated either, so i's just either on or off as well. No variable speed.

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,481
    edited June 27

    You can wire the DHW pump to the priority zone 4 so that only the DHW pump comes on when there's a call for hot water. Flip the "Priority" dip switch to "On".

    Screenshot 2025-06-27 at 7.41.48 AM.png
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • jamespet
    jamespet Member Posts: 14
    https://forum.heatinghelp.com/discussion/comment/1858863#Comment_1858863

    Yep. I have considered this and tried it a few times. The issue I had a few winters was that when water was heating and rooms were calling at the same time.

    I like the idea of the priority, but maybe not so much priority. I'm probably just asking too much of the system I have.

    It also messes with my heating logs. If a zone is calling and the DHW starts heating, the logs report that the zone is still heating even though it not.

    I should probably just get a 007e and call it good enough.

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