Honeywell DT90 wiring

Discussion in 'Electricians' Talk' started by Tonywillow86, Oct 29, 2017.

  1. Tonywillow86

    Tonywillow86 New Member


    I have purchased and fitted a DT90e to replace my mechanical thermostat! I have a unit in the kitchen which turns the water and central heating on / off then a thermostat in the hall.
    At the the thermostat location I have a red (live) blue (neutral) and earth. Is it correct I only wire the live to A and the neutral and earth are not used? The reason I ask is the when the system fires on the rads are not heating up could this be because of the new thermostat?
    Help is much appreciated and thanks in advance.
  2. Are you sure you do not have a yellow too.
    What thermostat did you remove? did you note the connections.
  3. Tony, we need a pic (or description) of where your wires went to the old stat.

    (You've removed it, haven't you...?)
  4. JP.

    JP. Screwfix Select

    Might help a bit

  5. JP.

    JP. Screwfix Select

    Should be very simple - the unit is battery powered thus its L in and swl out (the black wire which should be flashed) The op's present unit does not have a neutral black wire) but it is in fact the swl?
  6. He has a red and blue wire JP, that is why I suspect he has a 3 core cable at the stat and asked if he had a yellow cable.
    He will need to give answers to the questions asked above.
  7. JP.

    JP. Screwfix Select

    Agree Dobbs - more information required m8

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