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Using a pump relay to fire circulator for more then one zone/thermostat?

Falcon11Falcon11 Member Posts: 8
Hello fellow plumbers,
I have a Client that wants 11 different zones in his new house. I mostly do 3 to 5 zones all on a circulator relay from the thermostat. So what I want to do is install Viega flow control manifolds with the powerheads(zone valve on header) and put up to 3 zones all with there own powerhead and thermostat on one circulator.

So my question is: Say I have a Taco Pump Control Relay (6 zone option), 4 wire viega powerhead zone valves(which close 24v circuit on call from the thermostat, open the zone valve,and send 24v to the pump relay) Can I install the 24volt wires from all 3 zone valves into "zone 1" on the taco pump relay so I can use one pump for 3 zones?, Im wondering this because say one TT called for heat would the 24v supplied from the zone calling for heat cause the other 2 power heads to open from a back feed because they would all be in the same circuit? Or is there an easier way?

I don't want to use one circulator. I use the flow control headers because I can balance all headers at 1GPM per loop which gives you 2-4ft per second velocity which is the most efficient passing of heat into the concrete, With one circ I will not be able to get that 1GPM on 4000 feet of pipe.

I have attached an image of a drawing I made to give you a rough idea what I'm asking. Sorry I'm a messy writer.


  • Falcon11Falcon11 Member Posts: 8
    I've never used the powerheads before always just went right from thermostats to the relay to fire the circulators for each zone. I need the power heads to stop flow into the zones that are not calling for heat. Just wondering if this idea will work
  • STEVEusaPASTEVEusaPA Member Posts: 4,549
    I'm confused. Why not do it the correct way? For starters you could possible go with a Delta P circulator.
    Looks like you want the circulator to come on if any of the thermostats open any of the zone valves?
    -What size are the loops.
    For starters make sure you don't exceed the voltages. But you can use a ZCV403 for each group of 3 and depending on how you're piped, run a system circ (boiler loop) and the circ for those 3 zones when any zone calls. Look at the little inset on the lower left.
  • Falcon11Falcon11 Member Posts: 8
    Hey Steve I'm not an electrical guy at all, don't know a whole lot about that. I'm quoting the the job and looking to have 4 circs run the 11 zones so that I know the circs will get the GPM I want for manifold. Each zone will have its own thermostat. Was just wondering if that way I was thinking would work as I have to supply the controls for it. Just looking for info don't need to do it that way I asked at all. Just looking for input what controls I should get to pull that off I don't need to wire that way I'm open to all opinions.

    I plan on piping the boiler in direct return. With 2 to three manifold supplys off each circulator. So 4 circulators with 2 or 3 branches to the seperate manifold. 
  • Alan (California Radiant) ForbesAlan (California Radiant) Forbes Member Posts: 2,540
    edited August 23
    I don't know your exact setup, but if you figure 11 loops at 300' per loop at .6 GPM per loop, that comes out to 6.6 GPM which is no problem for one, small pump.

    When you figure the pressure drop of your system, it's not the total footage of tubing. Instead, it's only the one loop that will be the hardest to pump through - perhaps your longest loop. After that, you add your total GPM to figure your pump.

    On the RadPad image below, I set the pressure drop of 1/2" PEX to .6 GPM on the left, I can see the pressure drop of a 300' length of tubing is just below 4' of head, no problem for a small pump.

    Often wrong, never in doubt.

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  • STEVEusaPASTEVEusaPA Member Posts: 4,549
    Look at page 34, then look at the notes about system pump, which will be your zone pump on page 32 using the dry contacts, one circ per each zone panel.
    You should have the system properly designed. I would use Delta P circs as one regular circ won’t perform the same depending on how many zone valves are opened.
    What kind of boiler?
    What kind of emitters?
    How are you controlling water temperatures?
    Kind of confused as to how to bid a job without a complete design, and piping and wiring schematics.
  • Falcon11Falcon11 Member Posts: 8
    There's 11 headers and 19 loops around 4300 feet of infloor. Never sized Boler yet but it's going to be propane on demand with an indirect hot water tank as well. Infloor will be run around 100F. I like the idea of the auto adapting circulators. He literally wants every room to have its own thermostat for the infloor. But I want to run 3 manifold at a time one circulator for every three zones. 
  • Falcon11Falcon11 Member Posts: 8
    Steve I'm currently working on the quote that's why I'm asking. so I have all the controls and everything planned and priced. There are 11 different manifolds with 3 to to 1 loop each. I could use regular zone valves at the boiler but I really don't like them. They might last 1 year might last 10 years and restrict flow so much. 
  • Then, it's just as you said. From each one of your zone valve controllers, wire the "X-X Isolated End Switch" to the TT terminals of a Taco SR501 pump relay. It will turn on the system pump if any zone calls for heat.
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • Falcon11Falcon11 Member Posts: 8
    In my drawing at the top is very rough it's not showing all the manifolds just 3 of the 11. Just wanting to use like a 26-99 grundfos for every three manifolds but wired up so that it can run one, 2 or all three of the manifolds at one time. Very confusing I know Im trying to get away without using 11 circulators, and not using the old school zone valves either. 
  • Why do you want to use such a big pump? Do you want to blow your system into eternity? Do you want to price yourself out of a job?

    I recommend doing some research before going on. You can start here:
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • Falcon11Falcon11 Member Posts: 8
    Hahaha. Look all I want to know is can I put multiple zone valves in one slot of the pump relay. If I cant do that on a pump relay what control can I use to do it
  • Falcon11Falcon11 Member Posts: 8
    The viega thermostat goes directly to the viega powerhead zone valves to close the zone valve circuit and open the zone valve. The remaining 2 wires of the zone valve then go to a relay. Can I put more then one zone valve in that relay or do I kibosh the circulator relay and get individual relays and wire them in parallel to fire the circulator

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