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Chosing a hot water diverter for solar pv

  • 13-05-2021 9:12pm
    #1
    Registered Users Posts: 651 ✭✭✭ buzz11


    I'm looking to buy a solar immersion diverter for my 3.6Kwh panels and 500L hot water tank (no EV or plans for it) The water is currently heated by electric immersion on the night rate.

    Although my water tank has two immersions (3Kw half way and 6Kw at bottom), I don't think a dual immersion diverter is all that important - I'd be quite happy if the 3.6Kw panels can bring the 3Kw immersion to full temperature, and theres enough hot water to meet the needs of the house.
    If I had more panels, then I'd need dual immersion feature but theres little chance that I can add more panels to the roof.

    The available diverters that I've seen online are
    • Solar I boost €370 2yr warranty
    • Apollo Gem €375 5 yr warranty
    • Eddi €630 3yr warranty
    • Solic 200 £200 10yr warranty

    So the cheapest diverter has the longest warranty which is a crude way of comparing them....any advice?


Comments

  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    None of those make much financial sense unless you heat the water via the immersion? How do you heat your water right now?

    At the very least I'd wait until the details of FiT are known before departing with any of your hard earned cash.


  • Registered Users Posts: 651 ✭✭✭ buzz11


    KCross wrote: »
    None of those make much financial sense unless you heat the water via the immersion? How do you heat your water right now?

    At the very least I'd wait until the details of FiT are known before departing with any of your hard earned cash.


    Yes water is heated by electric immersion on the night rate, we never use the 6Kw element at the bottom - the 3Kw at the middle provides sufficient hot water for the house usage.


  • Registered Users Posts: 11,177 ✭✭✭✭ KCross


    buzz11 wrote: »
    Yes water is heated by electric immersion on the night rate, we never use the 6Kw element at the bottom - the 3Kw at the middle provides sufficient hot water for the house usage.

    Is the motivation to add a diverter to save money or something else?
    Any idea what you spend per year on heating water?

    I know it probably breaks your heart to see electricity going to the grid for free but you need a calm head here... spending hundreds on a diverter might stop you sending free electricity to the grid and give you hot water but you are just paying up front for your hot water to the diverter company instead... bear in mind that diverter has a finite life as well, it wont last as long as the panels.

    Thats why I'm saying wait until you see what FiT brings. It could be alright or it could be a disaster, we dont know yet.

    Another possibility is see if you can pickup a second hand diverter. That might be viable.


  • Registered Users Posts: 651 ✭✭✭ buzz11


    KCross wrote: »
    Is the motivation to add a diverter to save money or something else?
    Any idea what you spend per year on heating water?

    I know it probably breaks your heart to see electricity going to the grid for free but you need a calm head here... spending hundreds on a diverter might stop you sending free electricity to the grid and give you hot water but you are just paying up front for your hot water to the diverter company instead... bear in mind that diverter has a finite life as well, it wont last as long as the panels.

    Thats why I'm saying wait until you see what FiT brings. It could be alright or it could be a disaster, we dont know yet.

    Another possibility is see if you can pickup a second hand diverter. That might be viable.


    Sound advice there thanks ...I'm assuming the FiT will be dismal but I'll wait to see what happens in a few months. Also I'm currently on the old FiT of 9c until its replaced so can easily sit tight.

    The main motivation is utilising the surplus power within the home and with such a large hot water tank its ideal for that usage -- plus the insulation on the tank is brilliant so thats a big advantage.

    I like the idea of an secondhand diverter...will keep an eye out.

    Thanks !


  • Moderators, Sports Moderators Posts: 15,993 Mod ✭✭✭✭ slave1


    Hot water is also a convenient factor, I paid a lot less for my EDDI up north, it was an electrical supplier in Belfast, no idea what it’s called. EDDI is fanless so no noise compared to others.
    You mention 6kW element, not sure any diverter could handle that, think EDDI maxes at 3kW.
    We had 7 showers yesterday, all from diverted PV.
    Would you mind posting pic or brand/model number of your cylinder as ours is not up there when it comes to heat retention.


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  • Registered Users Posts: 651 ✭✭✭ buzz11


    slave1 wrote: »
    Hot water is also a convenient factor, I paid a lot less for my EDDI up north, it was an electrical supplier in Belfast, no idea what it’s called. EDDI is fanless so no noise compared to others.
    You mention 6kW element, not sure any diverter could handle that, think EDDI maxes at 3kW.
    We had 7 showers yesterday, all from diverted PV.
    Would you mind posting pic or brand/model number of your cylinder as ours is not up there when it comes to heat retention.


    Heres a pic with the details. I bought the cylinder in '14 and had an option of eco80 which was 80mm of external insulation - I'm not sure what the standard is nowadays.

    Yeah the 6kW element would need to be changed to a 3kW but I've a nice setup where if the middle element reached temperature then the diverter could then heat the lower element


    2021-05-14-08-45-02.jpg


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,818 CMod ✭✭✭✭ unkel


    That's a 500l cylinder. Nice :cool:

    We also have a Joule (360l - biggest that would physically fit into our hot press) installed in late 2016 and afaik the insulation is so good that the water only loses about 1C per 24h

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 651 ✭✭✭ buzz11


    The solic 200 that I mentioned in the OP appears to have a fundamental flaw in that you have to press the 'boost' mains button every 90 mins in order to keep heating the immersion by electricity...not practical during the long winter months.



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