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Immersion heater - economy 7 timer wiring

Former Community Member
Former Community Member
Hello,


I have a honeywell st6400c controller and an immersion heater. 

My heater has 2 switches, off and on peak. My concern is that the heating works only with both switches on. Even if its set to trigger at off peak time only, which it does, both switches light up and if I switch off the onpeak one, the heating stops even tho the offpeak is still lit (testing this at off peak hours ofc). Is this correct ? does this not use much more electricity? I was monitoring this and Im sure it goes against the "night" hours, but my worry is that it uses much more power than it should.

Thank you for your advice

Tom
  • Former Community Member
    0 Former Community Member
    Hi,


    cant upload a picture i keep getting some system error msg. 


    anyway, its an electronic radiator which has got a little box attached to itself at the bottom corner - from which goes a wire to a socket with a switch on it.
  • 0
    Tom Luknar:

    Hi,


    cant upload a picture i keep getting some system error msg. 


    anyway, its an electronic radiator which has got a little box attached to itself at the bottom corner - from which goes a wire to a socket with a switch on it. 


    As Sparkingchip says " So it sounds like someone has made up a homespun control unit using relays." so without actually seeing everything would be imposible to even guess what is going on.

    Edit to add I would be getting on to the meter operator as it would appear you are all electric and that could be a large load returning on the neutral wich at best is onlt a 10mm.


  • 0
    so what is the 80amp neutral for?

    Typiod:
    Blencathra:

    80amp neutral? are you an ex board man, I was with NORWEB, whats the other neutral for straight out of the cut out?


    Blencathra yes worked for SEB ( as an installation inspector, on the meter department for a few years) amongst other things. Are you talking about the small Neutral coming out of the head, if so that is going into the time switch, that is were the installation neutral is returning. The 25 mm neutral goes from the head into the meter then upto the phase block and from there is goes nowhere.




     


  • Former Community Member
    0 Former Community Member
    16.81p per kwh day rate

    9.18 night
  • 0
    Blencathra:
    so what is the 80amp neutral for?

    Typiod:
    Blencathra:

    80amp neutral? are you an ex board man, I was with NORWEB, whats the other neutral for straight out of the cut out?


    Blencathra yes worked for SEB ( as an installation inspector, on the meter department for a few years) amongst other things. Are you talking about the small Neutral coming out of the head, if so that is going into the time switch, that is were the installation neutral is returning. The 25 mm neutral goes from the head into the meter then upto the phase block and from there is goes nowhere.




     




    The 80Amp neutral would be for the off peak load (ie storage heaters), like all old time clocks the live and neutral would pass through the timeswitch, however not always, sometimes the neutral from the off peak board would get wired straight into the head.


  • 0
    Never seen that, only switched live, where is it going ?
  • 0
    Tom Luknar:

    16.81p per kwh day rate

    9.18 night


    Getting a grip on the usage in your installation is going to take some doing, you have a “third rate” free electricity when the sun is shining.


    If you don’t have storage heaters and you aren’t heating your hot water overnight, you are not making use of the 9.18 pence nighttime rate and may be over paying on the daytime rate.


    You may be better of spending a lot of money on storage heaters and/or using the E7 immersion heater if your general daily load matches the output of your solar panels.


    It sounds like you have not been in the house long enough to have bills to work out what’s your usage is.


    It might be a good setup, it might not, we can only speculate. As to how and what the timer does, I cannot tell you.


     Andy B.


  • 0
    I can't vouch for the terminal ordering/position, but the wires to the timeswitch look to be about what I've seen before around here. Meter output goes to a DP Henley, from there L comes back to the timeswitch where it's SP switched to provide the off-peak supply - which goes past the side of the henley up to the CU, N to the CU comes straight from the Henley. I'd expect another L (and probably N) to the CU direct from the henley to provide the 24h supply,  but can't quite see that in the photos (possibly be hidden behind the off-peal tails). The smaller wires are fused down to provide power to the clock and a switched N to prompt the meter to switch recoding between the peak and off-peak registers.


    It might make more sense if we could see the CU(s) and this st6400c - together with any associated equipment e.g. any contactors/relays.

       - Andy.
  • 0
    DBlencathra:

    Never seen that, only switched live, where is it going ?


    E7 smart meters have a a switched neutral controlling the relay.


    Andy B.


  • Former Community Member
    0 Former Community Member
    Been here almost a month, from day 2 ive created myself an "electricity spreadsheet" and was putting down the usage. it came to about 2kwh a day and 6 a night. did this for a week. 

    - i believe ive mentioned it in the post that i know the electricity goes against the night rate as ive set the controller up that way. the heating of water goes from 5am to 6.20 which is still the night rate. im just concerned it devours somehow way more than it should. need to start measuring again to doublecheck i guess

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