1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

fuse blows after installing timeswitch

Discussion in 'Electrics UK' started by mm82, 27 Nov 2021.

  1. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi,

    we've recently had a timeguard NTT03 timeswitch installed to an immersion heater that was always on,
    but the fuse (13A) keeps blowing after maybe an hour or so and I'm not sure why,
    do this connections look about correct to you?
    thanks in advance.
    timeswitch.jpg 15775471430488401796345771421623.jpg
     
    Last edited: 27 Nov 2021
  2. Sponsored Links
  3. flameport

    flameport

    Joined:
    10 Mar 2007
    Messages:
    10,082
    Thanks Received:
    2,033
    Location:
    Poole, Dorset
    Country:
    United Kingdom
    What rating is the heater?
     
    • Thanks Thanks x 1
  4. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    thanks for the help Flameport! I'm a bit of a newbie and not sure if this is what you're asking but the label shows:

    2 x 3kW @ 240Vac 50HZ
    2 x 2.8kW @ 230Vac 50HZ

    PXL_20211127_115648955.jpg
     
  5. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    9,483
    Thanks Received:
    1,283
    Country:
    United Kingdom
    You can only power one of the two elements, via a 13amp fuse. The usual arrangement with two elements, is a short element and a longer one. The longer one can heat up the entire cylinder, so is usually on a timer for heating on off-peak E7. The shorter one is normally used during peak when the energy costs more, often on a press to run one hour button, but only heating the upper part of the cylinder.
     
    • Thanks Thanks x 1
  6. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks Harry,
    we don't have a dual meter so we wouldn't be taking advantage of having the 2 elements. which is also the reason why I wanted to have a timer so its not on all the time.

    anyway how would I go about fixing this? (again as a total newbie and even if temporarily so I can get some hot water before someone who knows what they're doing comes to fix it properly if needed).
     
    Last edited: 27 Nov 2021
  7. CBW

    CBW

    Joined:
    26 Sep 2019
    Messages:
    9,663
    Thanks Received:
    2,642
    Location:
    North
    Country:
    United Kingdom
    Is this powering one element or both? What was there before?
     
    • Thanks Thanks x 1
  8. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    @CBW sorry I don't really know if its powering both or if it was, before there was a switch like this
    PXL_20211127_115036001.jpg PXL_20211127_122043615.jpg
     
  9. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    9,483
    Thanks Received:
    1,283
    Country:
    United Kingdom
    That timer is probably not designed to supply two elements, from what I can see - if you were to remove one of the two browns from the rightmost terminals and add a connector to make sure it is insulated, it would enable you to get one of the two elements working temporarily. If you can check and make sure it is the brown for the shorter element, even better, but...

    If only a small amount of water gets hot at the top, swap the brown you have removed, for the one the one still in that rightmost terminal.

    Where is the fuse located, which is blowing?

    I think your original setup allowed one element, or the other, but not both at the same time.

    Do you actually have an E7 off-peak metered supply?
     
    Last edited: 27 Nov 2021
    • Thanks Thanks x 1
  10. Sponsored Links
  11. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    @ Harry, brilliant thanks so much!!
    is there any way to figure out which is which? and just to understand, how come I should have the shorter element connected rather than the longer one in my case?
     
  12. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    9,483
    Thanks Received:
    1,283
    Country:
    United Kingdom
    No, you need to have the longer element connected to the time clock, in order for a full cylinder of hot to be produced when the timer switches on.

    The shorter element is intended for 'on demand' hot water, or a quick boost during the day, when E7 is at peak rate cost. That, rather than a simple switch, often uses a push button timer so it can only stay on for an hour or so if pressed.
     
  13. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    ah right, makes sense thanks!
     
  14. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    9,483
    Thanks Received:
    1,283
    Country:
    United Kingdom
    Where was the 13amp fuse located, which blew and are you on some sort of off-peak meter?
     
  15. mm82

    mm82

    Joined:
    27 Nov 2021
    Messages:
    17
    Thanks Received:
    0
    Country:
    United Kingdom
    no we don't have an off peak meter, the fuse is located in a separate a power switch that feeds the timer:
    PXL_20211127_125913963.jpg
     
  16. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    9,483
    Thanks Received:
    1,283
    Country:
    United Kingdom
    OK so probably you only need to have the longer element on the time clock.
     
  17. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    75,010
    Thanks Received:
    4,349
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    So what do you hope to gain by using a timer?
     
Loading...

Share This Page