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Horstmann E7BX installed but no dual rate meter

Discussion in 'Electrics UK' started by NeilTheNovice, 12 Aug 2021.

  1. NeilTheNovice

    NeilTheNovice

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    Have recently moved into a property and having a bit of a nightmare with the power companies. In short, there used to be storage heaters (no gas in the building) and these were swapped out 3 years ago. At the same time, the dual rate meter was changed for a single rate one which the previous owner didn't follow up and was paying for estimates for a meter which didn't exist. Anyyyyway, the water tank has two 3kw elements as you might expect but because there's no "off-peak" supply anymore, the bottom heater does not come on overnight as it would have previously.

    The boost function of the E7BX powering the top element works OK but it only heats the top third of the tank, again as expected. I've bought a Timeguard TRTD7N as a potential replacement to use the bottom element to heat the tank overnight but the issue is that it has half the terminals of the E7BX. It says it's suitable for dual/twin elements so my question is, can I just terminate the old mains "off peak" supply being fed to the E7BX (terminals 1 and 2) and run the new timer from the mains supply (which runs to terminals 3 and 4 of the E7BX).

    Any advice appreciated!
     
  2. AndyPRK

    AndyPRK

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    you can connect both elements to the Timeguard TRTD7N

    The bottom element will work off the timer.
    The top element will work when you press boost

    In answer to your question, I would say yes
     
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  4. NeilTheNovice

    NeilTheNovice

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    Thanks for the reply, going to give it a try this weekend and hopefully it's fine. Fairly happy that as long as I terminate the old off-peak supply and the "peak" supply is connected, being able to control both elements is going to "just work" as the logic is in the controller, rather than the off-peak signal being required from the power company to heat the tank overnight.
     
  5. ericmark

    ericmark

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    Economy 7 is a tariff not a system, in the early days we had two separate meters, the white one only switched on at night, and often two consumer units/fuse boxes as well, but then it moved to having one supply and often a signal to tell heaters when to heat, but could also be a simply timer.

    What must be avoided is borrowed neutral, this can be dangerous, the line and neutral should run together, so the neutral can't in error be disconnect and then become live due to a supply from some other point. This would be an easy error to make when combining the two consumer units or meters, so you need to be very careful.
     
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  7. AndyPRK

    AndyPRK

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    Also you don't need to heat the tank all night.
    5am-7am should be plenty
     
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