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adding zone valves to a multi curculator system

Benn a lurker for a bit but this is my first post looking for help.  I currently have a two zone hot water radiant floor system using a Dunkirk boiler and 2 grundfos circulators controlled by a Azel SP82 2 zone switching relay. Were adding on to our home and need to expand the system so Id like to take a branch from one or both of the current zones by using zone valves. My question is what do I need to do to operate both pumps and 4 zone valves from 4 thermostats? Is it as simple as changing to a 4 zone switching relay or piggybacking another 2 zone onto the existing? if so how do I power the proper pump (say that 10 times fast) when individual zones call for heat?

Thanks in advance for you help.


  • Big Ed_4
    Big Ed_4 Member Posts: 2,076
    Extra Zone

    You would wire the end switches to the thermostat terminals on the Azel control ... But with out looking at the set up I would have to guess your better off expanding using circulators and joining a second control using the I-Link ... Assuming mixing vales are used and set to set each radiant zones proper floor temperatures .
    I have enough experience to know , that I dont know it all
  • Ecubed
    Ecubed Member Posts: 2

    I use one honeywell MX mixing valve right now but am fine with adding one if the calc's call for it which it probably will, we're spray foaming that whole new portion of the house so heat loss will definitely be less. My system uses a 1 1/4" copper manifold attached to the basement wall, space is tight there and was hoping to avoid butchering it to add a pump(s), but I think I can work that out..

  • kcopp
    kcopp Member Posts: 4,093
    Your better...

    off eliminating one Circ. pump and doing 4 zone valves. Much cleaner and simple.... simple is good.
  • gennady
    gennady Member Posts: 839

    If you are adding 2 zone valves, to additional loops, you have to add zone valves to existing loops as well and then you will need another switching relay, designed for 4 zone valves.

    you cannot just add 2 zones with zone valves, because if one of new zones will call for heat, and trigger pump, then your existing zone will be overheated. But considering cost of relay and circulator, i would just add 2 circulators for 2 new zones and add 1 switching relay for 2 pumps. it will be cheaper, as you do not need to modify your existing system
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