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Electric shower - options for increasing pressure?

Discussion in 'Plumbing and Central Heating' started by sdss, 9 Apr 2013.

  1. sdss

    sdss

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    I've got a Mira Vie electric shower but the pressure isn't great at all. What are the options for replacing it or improving the pressure.

    (The bath has a shower attachment off the taps and the pressure on via (from the boiler) and with a similar shower head is excellent).

    Are there any options and what's the best option?

    Thanks in advance for any advice
     
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  3. newbuildinstaller

    newbuildinstaller

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    electric showers are always limited by their size in KWs, they can only heat water by "x" degrees at "Y" flow rate. The hotter you want the water the slower the flow, this gives the water longer inside the heat exchanger which makes it hotter.

    It sounds like you have a combi boiler so the best/cheapest way to have a better shower is to replace your electric shower with a standard thermostatic mixer shower. That way you are only limited by your mains water comming in and the size of your boiler (which will be at least 3x the size of your shower)
     
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  4. sdss

    sdss

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    Thanks for the reply.

    The only issue I see with that is getting the hot water to that shower - it's a new build property so can't imagine that they'll have given that any consideration although I may be wrong.

    What about electric "power showers" - I understand some have integrated pumps. Are these likely to offer any considerably better performance? Any know how noisy they are?

    Again thanks
     
  5. newbuildinstaller

    newbuildinstaller

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    A non starter mate, You can only pump stored water (tanks in the loft and copper vented cyclinder in the airing cupboard) and again you would need a hot supply to the shower.

    Without seeing the layout it would be hard to advise. It may turn out to be more trouble than its worth to find another hot to the shower location.

    Also its worth knowing that new build do this with one electric shower and one mixer shower when a combi boiler is installed. They do this so both showers can be run effectively at the same time. With two mixer showers from the combi, the boiler may struggle to heat enough water to run them both at the same time. This would mean warm/cold showers not hot A typical combi will supply 10-15 litres/min of hot water this is more than enough for one good shower but not enough for two.
     
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  6. sdss

    sdss

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    Thanks for the reply.

    Is there much actual difference with the through put of electrical showers? I know their stats show differences but is this likely to be noticeable if the whole unit is replaced?

    Yet again - thanks
     
  7. denso13

    denso13

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    Higher KW shower should give you better flow rate at the same temperature but this might mean increasing the cable size. Maybe better fitting a thermostatic shower, although more work involved.
     
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  8. bolshy

    bolshy

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    Any new electric shower above 8.5 kW should now have a 10mm² twin and earth cable rather than a 6mm². 8.5 kW still won't give a decent shower in winter.
    A 10.5 kW shower would give a good flow rate in winter, but would require the cable upgrade to 10mm and also a 45A MCB if the consumer unit has RCD protection, or a 45A RCBO if not.
    The only easy fix is to use a water saving pulse shower head.
     
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  9. sdss

    sdss

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    Thanks for all the replies.

    The current circuit has a Wylex B40 on it.

    The shower would have been fitted in the last two years and is a Mira Vie. Is it likely to have had the 10mm cabling?

    How big a job is replacing the cable if the thinner one has been used?

    Again thanks for the replies
     
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  11. sdss

    sdss

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    I found a "Domestic Electrical Installation Certificate"

    for "Circuit designation" "shower" under "Circuit conductors: csa" / "Live (mm2)" is has "10" and for "cpc (mm2)" it has "4".

    Does that mean I could potentially have the unit switched over with relative ease to a 10.8 kW one?

    (i'm assuming my current one is 8.5 kW or 9.5 kW as the Rating seems to be 40A, whereas it looks like a 10.8 kW one would need a 45A instead).

    I hope that makes some sense.
     
  12. bolshy

    bolshy

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    A 10.8 kW shower would need a 50A RCBO.
    Get an electrician in to sort the circuit. He will be able to advise on the circuit requirement, and whether the meter tails are adequate.
    The only other thing you need to be aware of, is you could approach your main fuse/main isolator limit at certain times of the day if the shower is on at the same time as other larger loads in the house. With an electric oven, tumble dryer, a TV or two, fridge freezer, recessed mains lighting etc plus all the other bits and bobs, flicking on the kettle whilst someone is in the shower might make it go dark. :mrgreen:
    As for the 10mm twin and earth, it seems you have struck lucky.
     
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  13. sdss

    sdss

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    Thanks for the reply.

    And thanks to you all - it looks like swapping the current unit with the Mira Vie 10.8kW seems to be the easiest solution as it looks like it'd just need the RCBO switched over too, and presumably that'll all be an easy job for an electrician.


    The "Domestic Electrical Installation Certificate" also lists the "Maximum demand load" as 60 Amps - does that make it likely that it likely that the demand could be too much, or just a technical possibility?

    thanks
     
  14. xr4x4

    xr4x4

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    I'm guessing you have a combi boiler?

    Is the shower in the bath? Or a separate shower? If it's the bath, why can't you just use the mixer tap/shower head attachment to shower with?

    If its a shower cubicle, does it have access space above? Because aqualisa do a exposed digital shower which can be fitted without damaging the tiles.

    All you need is hot and cold to the processor above the shower and power.
     
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  15. Johnwayne2

    Johnwayne2

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    You can buy a pump now that you can fit on cold main to improve pressure,think it`s about 200 quid tho.
     
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  16. mogget

    mogget

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    Which will make absolutely no difference to the flow. You can only get 'so' much flow out of 'so' many kilowatts.
     
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  17. sdss

    sdss

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    the combi boiler feeds the bath/shower attachment to the bath. But the electric shower is in a different room

    from what I understand and from the other advice (above) - I don't know if that'd help as it seems its the electric shower that's lowering the pressure rather than low pressure being the issue in itself
     
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