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Taco zvc404 with triangle tube prestige excellence questions

First time post here and I'm sure I will probably forget something important but I will try and give as much background information as possible. I'm a big DIY'er who is fairly competent.

The system I am working on is a combination hydronic heat with DHW with Triangle tube prestige excellence. The old zone control was a Honeywell Aq250 which was replaced with a Taco zvc404. The problem we were having was that the thermostat would call for heat but the zone control was not sending that call to the boiler. It would not close the circuit at the T T terminals. This did not happen all the time but seemed to only happen with large temp swings. A simple reset at the breaker would fix the problem and heat would come on and work well until the next time. This was happening about 3-4 times a month.

I was able to replace the zone control and the heat side works. My question is about the DHW priority setting using the 4th zone. The Honeywell only had the T T wires and the 120 Hot, neutral and ground wires that were connected to the boiler. The Honeywell had a light that would come on when there was a demand for hot water and I'm assuming that it would shut off the zone circulation pump. For the life of me I can't figure out how the honeywell zone control knew when there was a demand for hot water?

Right now the boiler will move priority over to hot water when there is a demand for it but the zone circulation pump still runs. Do I need to run another wire from the boiler to the 4th zone and if so from where? Do I even need to worry about the zone circulation pump running and just let the boiler deal with it?

I apologize if some of my descriptions are not very clear and appreciate any help.

Comments

  • IronmanIronman Posts: 5,468Member
    edited December 2019

    Some pics would really help.

    Probably, the simple solution would be to run a wire from the "system circulator" terminal on the boiler to one of the "X X" terminals on the ZVC and the connect the system pump to the other "X" terminal.

    The boiler will de-energizes the system circ during a domestic call.

    All of this is predicated upon the DHW circulator being Tee'd at the boiler and not being piped off of the secondary.



    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • dahlenburgdahlenburg Posts: 4Member
    Ironman said:


    Some pics would really help.

    Probably, the simple solution would be to run a wire from the "system circulator" terminal on the boiler to one of the "X X" terminals on the ZVC and the connect the system pump to the other "X" terminal.

    The boiler will de-energizes the system circ during a domestic call.

    All of this is predicated upon the DHW circulator being Tee'd at the boiler and not being piped off of the secondary.



    Thanks for the reply. I will try and take some pictures when I get home tonight. I'm starting to think that it may not have been wired correctly in the first place. I'm going to try and upload a picture of the furnace wiring and see if it works. The circled wires are currently the only thing connected to the valve control and some how it worked with the old honeywell control.
  • dahlenburgdahlenburg Posts: 4Member
    When you mention tee'd at the boiler is that the same as having a diverter valve?
  • ZmanZman Posts: 5,533Member
    I don't think it is a big deal that your system circ is spinning when you have a DHW call. The diverter valve in the Excellence is sending the heat to the little indirect, so the system circ is just circulating (not so hot) water around.
    If you want the system circ to turn off during DHW, it would be easiest to wire it to the Triangle Tube instead of the Taco and adjust the settings as needed.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • dahlenburgdahlenburg Posts: 4Member
    > @Zman said:
    > I don't think it is a big deal that your system circ is spinning when you have a DHW call. The diverter valve in the Excellence is sending the heat to the little indirect, so the system circ is just circulating (not so hot) water around.
    > If you want the system circ to turn off during DHW, it would be easiest to wire it to the Triangle Tube instead of the Taco and adjust the settings as needed.

    Thanks, that's pretty much what I wanted to know. After reading all the manuals it does seem much easier to wire directly to the boiler
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