Which wires to connect?

We are replacing our DanfossTP7001 I have taken the old unit off but there are only 2 wires connected, the Hcom and Hon with a yellow and green one not connected to anything any ideas?


  • I probably should have mentioned that we are connected to District heating :)
  • Assuming you are connecting a wired thermostat.

    Hcom goes to COM

    Hon goes to NO

    If you need to make the yellow and green wires safe you can connect them to P1 and P2. These are just parking terminals and have not electrical connection.

  • AKilbride
    edited February 2021
    So on the setup instructions it asks to label 3 wires but there is no NC wire do I not need to worry about it is that the green and yellow one?
  • Yes, you can ignore NC. NO and NC are just opposite poles on the relay switch. When NO is live then NC will be off and vice-versa. NO and NC cannot both be live at the same time, nor can they both be off.