Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

TPI Aquastat Wiring

sasquatch16 Member Posts: 10
Looking for some guidance wiring aquastat on new indirect water heater. Current aquastat just uses 2 low voltage wires. I believe they are 24v hot and aquastat makes and breaks connection. New TPI aquastat has 2 wires in and 2 out. Does this have to have
a common wired to it to work?


  • sasquatch16
    sasquatch16 Member Posts: 10

  • STEVEusaPA
    STEVEusaPA Member Posts: 5,319
    We're missing a whole lot of information before making some suggestions.
    Typically the indirect is it's own zone, either controlled by circulators, or zone valves.
    You'll need to supply 24 volts from a transformer or from a zone control.
    Some zone controls and boiler controls have terminals for an indirect so to control it's own zone.
    What type of new indirect and why wasn't it supplied with an aquastat that isn't 50 years old?
  • sasquatch16
    sasquatch16 Member Posts: 10
    New tank supplied with the new aquastat pictured. Current setup has its own circulator on boiler with 2 wires hooked up to old aquastat that go to control
  • kcopp
    kcopp Member Posts: 3,825
    The 2 terminals on the left go to the TT like there was on the old aquastat... You need to run 24v to the other terminals on the right.... Wiring.pdf
  • sasquatch16
    sasquatch16 Member Posts: 10
    Thank you