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Grundfos UPZCP-3, 3-Zone Pump Control - Set-up?

HydronicolicHydronicolic Member Posts: 12
I have a 2-zone RFH system being heated with a Tankless Heater. I have the 3-Zone Pump control set-up with the Tankless pump on the 3rd zone relay. I wired the End-switch terminal over to the TT terminal on the 3rd relay thinking, on a call for heat, the end-switch will make and start the Tankless pump. When ALL calls are satisfied, the End-switch opens and the Tankless pump shuts off. What is happening: it works on the start-up, but when ALL zones are satisfied, the End-switch doesn't open unless I kill power to the Control, leaving the Tankless pump running continuously. THE QUESTION: Is there a way to make this work?


  • hot_rodhot_rod Member Posts: 13,318
    A single pump system? Does the tankless supply DHW also? Or just dedicated to heat?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • HydronicolicHydronicolic Member Posts: 12
  • HydronicolicHydronicolic Member Posts: 12
    I've used a separate single zone relay in the past but thought, "what the heck" save the cost and labor of the 2nd control.

    I was wondering if tying in a resistor between the E.S. and the 3rd Zone relay TT might create enough load to make this go away, while realizing I'm not an electrical engineer.
  • hot_rodhot_rod Member Posts: 13,318
    If you are trying to control 3 circulators a ZVR?

    \The ZSR is the control for switching circulators Zone Switching Relay

    The ZVR Zone Valve Relay is a 24V relay for powering zone valves.

    There may be a work around

    You have 2 zone pumps and a boiler primary circ that needs to run with either zone circ?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • HydronicolicHydronicolic Member Posts: 12
    edited March 7

    That is correct. 2 Zone pumps, and 1 Heater pump on the 3rd Zone relay contacts.
  • Wire your primary pump to the "Primary Pump" terminals with all the dip switches in the off position. Remove the wires from the end switch to zone 3 TT terminals.

    Often wrong, never in doubt.

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  • DYIDYI Member Posts: 9
    I see a problem with the vent pipe connection to the Takagi boiler. The installation manual says the vent pipe must be inserted inside the collar, not outside. This is to ensure that a leak-free seal can be made with the o-ring inside the collar.

    Here's what my last Takagi install looks like.

  • HydronicolicHydronicolic Member Posts: 12

    Good eye! That was "By others". It was originally vented with galvanized. I called that one and the plumber friend came back and screwed it up more professionally.
    Alan (California Radiant) ForbesCanucker
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