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TT smart indirect water heater and viessmann DHW sensor

iz Member Posts: 10
I have a Triangle Tube - Smart 40 indirect hot water heater and a Viessmann 200 hot water mod-con boiler. How do I interface the two together? The TT Smart 40 comes with a built-in sensor but the Viessmann manual says to only use a Viessmann DHWH sensor. Do I have to replace the integral TT Smart sensor with the Viessmann sensor?


  • Kevin__Flynn
    Kevin__Flynn Member Posts: 74
    You have two choices...

    You have two choices.

    You can use the aquastat that is already installed inside the Triangle Tube and use the "External Demad" feature on the Vitodens 200. This will however, require an additional switching relay to power the DHW pump.

    The better choice is to remove the tank's aquastat and drop the sensor down the tank's well. One word of advice; drop the Viessmann sensor down the well until it hits the bottom, and then pull it up about 1/2 an inch. If you're creative, you can actually splice the Viessmann sensor to the back of the Triangle Tube terminal strip for a nice clean look. Then you can run a 2-wire from the aquastat connection to the boiler. This option allows you to utilize the DHW pump output (#21) to power the DHW Pump. It also allows you to set the DHW temperature on the boiler as well as use the DHW setback timer, if desired.
    Kevin Flynn
  • iz
    iz Member Posts: 10
    will look at it tonight

    Kevin, thanks for the input.  I will look into this tonight.  I intend to use the Viessmann sensor as I want control via the boiler controller, especially because I purchased the remote controller so that I can do all of the controls from the main living floor.

    Out of curiosity what is the advantage of lifting the sensor 1/2" after contact with the bottom of the well?
  • gennady
    gennady Member Posts: 839
    edited August 2012

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