How do I wire multiple zone relays ...

Discussion in 'HVAC Heating & Cooling' started by ptwohey, Nov 29, 2009.

  1. ptwohey

    ptwohey New Member

    Messages:
    3
    Location:
    RI
    I am upgrading my old heating system with a larger WM with a tankless that comes prewired with an aquastat with one zone and the ZC and ZR terminals for additional zones.

    My question concerns the ZC and ZR terminals. What do they do? With the old system that had similar wiring, I expected that no zones would operate if the boiler water was not hot enough to trip the aquastat. What I found is that even when the oil gun was not operating and water was cold, the circulators would run.

    I have a Taco multiple zone relay in addition to the factory to run 4 circulators and would hope to take advantage of everything the factory aquastat has to offer. I am not sure if I need a seperate aquastat for each relay.

    Thanks, PT
  2. ptwohey

    ptwohey New Member

    Messages:
    3
    Location:
    RI
    I'm back and replying to my own thread.

    I studied the wire diagrams for both the aquastat and zone controler. They are contradicing when it comes to the line voltage source.

    The aquastat shows that ZR and ZC are the hot and neutral 120V controled by the temperature relay that could provide the voltage to the zone controler and I verified that 120V is supplied once it reaches the set low limit. The zone controller has the ZR and ZC terminals but also has H and N for supply voltage. The diagram shows that if you add H and N you override the two Z's so the aquastat has no override.

    My observation is something that TACO will need to explain as it is not clear on the use of the 4 terminals so I will call them in the AM. Until that happens I will disconnect the H and N and leave ZC and ZR connected to see what happens.
  3. Thatguy

    Thatguy Homeowner

    Messages:
    1,460
    Location:
    MD
    Post the diagrams.
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