Solar Immersion Controller… Can I bypass?

  • June 25, 2018 at 17:21 #25336

    Hi all,

    This might just be a basic electrical wiring question, but please bear with me…

    I currently have UFH which adds to the hot water tank, but also an immersion which is used to top up the water and take it to over 60 degrees once / twice a week (to stop any legionnaires disease). This is currently controlled by a 3kw lightwave in line relay, which works fine. I also have a Solar PV system which helps to provide electricity, (have no gas, oil etc)

    However I’ve just discovered the existence of these little beauties:

    Basically they measure if I am sending electricity back to the grid, and if so re-route it to my immersion, so the water is always hot, and it doesn’t cost me any money. (My Feed In Tariff is set so 50% of whatever I produce is paid as if I’ve sold it back to the grid).

    Now, the actual question:
    If I installed this, could the LW relay be wired “alongside” it to remotely boost the hot water if needed? Basically, could the immersion heater be fed by two power sources, or is this not possible / practicable or just dangerous / impossible?

    Sorry for the long drawn out post, and thanks in advance for any help / advice.

    June 25, 2018 at 20:10 #25337

    I can heat my water with gas so not a direct comparrison. I also use a unit to use up any surplus power from my solar panels. The unit messes with the shape of the waveform into the immersion heater so if only 456 W are surplus it only feeds 456 W into the heater element.
    It is not damaged if the load suddenly dissapears e.g. when thermostat cuts in. You would need to use a seperate relay powered from your lightwave relay to switch the element between mains and the solar unit output.

    Lightwave Link (930) + 10x TRV (922) + Thermostat + Boiler Switch- London, UK

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