Thermostat wire colour query - should yellow be switched ?

Discussion in 'Plumbing and Central Heating' started by jamesb72, 27 Dec 2012.

  1. jamesb72

    jamesb72

    Joined:
    27 Dec 2012
    Messages:
    2
    Thanks Received:
    0
    Location:
    Somerset
    Country:
    United Kingdom
    I want to change the mechanical thermostat for a programmable room stat, both to have a 'night temp' and better programming.

    The current mechanical thermostat has 3 wires which I've tested and found:
    red/orange - live
    yellow - neutral
    blue - switches live as thermostat is moved, ie live for demand

    My only concern is why blue is switched and yellow is live, I'd expect the other way round, but as I've checked this with a meter I am just going to use them as is.
     
  2. denso13

    denso13

    Joined:
    22 Jan 2007
    Messages:
    6,762
    Thanks Received:
    1,189
    Country:
    United Kingdom
    If you get a two wire stat you won't need the neutral connection.
     
  3. Sponsored Links
  4. Agile

    Agile

    Joined:
    26 Jun 2004
    Messages:
    64,088
    Thanks Received:
    4,604
    Location:
    London
    Country:
    United Kingdom
    There is no standard way to use different colour wires.

    Different installers do what they choose and sometimes you would think its intended to confuse people.

    Thats why it should always be carefully tested.

    You only need to use the live and switched live wires!

    Tony
     
  5. jamesb72

    jamesb72

    Joined:
    27 Dec 2012
    Messages:
    2
    Thanks Received:
    0
    Location:
    Somerset
    Country:
    United Kingdom
    Thanks for replies, puts my mind at rest that it isn't a bodge job and this is normal :LOL:

    I chose a mains room thermostat as I figured it will be easier than having to change batteries (Horstmann AS1 as I like the simplicity of its display), so will use all three wires, and set the original timer to always on for heating so this room thermostat will control temperature all the time.
     
  6. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
  7. Sponsored Links
Loading...

Share This Page