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Wiring multiple taco relays with zone valves and pumps

Building a new system and at the wiring stage, I have a few wiring questions.

My system
I have 7 radiant zones, each with their own pump.
I have 3 baseboard zones that use a single pump and 3 zone valves.
I'm all setup for indirect as soon as purchase the tank.
I have a Taco 504 priority and a Taco 506 priority.
Taco 5003-C3 zone valve
Grundfos pumps

1. How do I wire the relays together to create one big relay?
2. Which relay would the DHW attach too?
3. How do I make it so that my single pump controlling the three zone valves is only activated when any one of the 3 baseboard zones are activated while not the pump is not activated when any of the other radiant zones call for heat and the baseboard doesn't call for heat?
4. where are all the pumps wired too?
5. Is it recommended to tie the boiler low cutoff / boiler thermostat to the relay? I have a new weil mclain gv90+6

thanks in advance.


  • Leon82
    Leon82 Member Posts: 684
    I believe one needs to be an exp , expandable and there is an expansion port to connect them. there are diagrams with a bunch of wiring situations on their website
  • Leon82
    Leon82 Member Posts: 684
    I'm not sure if one of them is a zone control, but it is needed for the zone valves
  • njtommy
    njtommy Member Posts: 1,105
    The Taco ZVC controls will work better for what you are trying to do. Like Leon said make sure you get 2 of the expandable ones so you can link them together to control the boiler. It will be very easy to wire them and control them this way.
  • njtommy
    njtommy Member Posts: 1,105
    Wait I take that back so 7 pumps you have just for the Radaint loops?
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,645
    Unless you have some extenuating circumstances, the vast majority of residential systems only need one circulator. I generally use one for your baseboard and indirect, each with a zv. You may be able to do the same with the radiant one pump and manifold actuators or zone valves depending on the layout.

    So two circs.

    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • bumthun
    bumthun Member Posts: 2
    I would use 2) TACO SR504-EXP for radiant and 1) TACO ZVC404-EXP for baseboards. Set your Indirect DHW to the priority on your master controller. You can daisy chain these controls together to have one master and two slave controllers. Go to http://www.taco-hvac.com/ for the wiring diagram. They are very straight forward with their wiring diagram.
    You'll also want mixing valves for the radiant zones, since these will most likely need cooler water than your baseboard loop.
  • hot_rod
    hot_rod Member Posts: 20,809
    Really need to see how you are piping to answer best. Is it a primary secondary? How are you mixing the radiant down?

    There is no limit to how many boxes can be combined. You should be able to select the priority for DHW indirect and select logic for primary secondary system pump, boiler pump and zone pumps.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Dave H_2
    Dave H_2 Member Posts: 535
    Take a look here, there are couple of videos to watch that describe almost exactly what you are looking for. Look for Wiring for Hydronics, Part 2 flopro.taco-hvac.com/flopro_u_courses.html

    Dave H
    Dave H