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Heating and cooling: Fooling an electric shower?

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1 to 26 of 26

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  1.  
    Hi
    I have solar hot water and a basic electric shower. I also have a spare mixing valve. What I want to do is feed the cold input of the shower with the mixed output of the solar TS and cold; setting the temperature to say 30'C. The idea being that the electric shower would either not heat the water or top it up to the set level, but using less electric overall.

    Has anyone else tried this? Is there a flaw in my cunning plan?

    Cheers in advance.

    Dave
    • CommentAuthorjms452
    • CommentTimeJun 14th 2012
     
    I think that electric showers tend to use a set amount of power and modulate the flow to get the desired output temperature so you may only suceed in getting a more powerful (and more likely to overheat/break) shower.

    If you have solar thermal wouldn't it make more sense to just to use the mixer valve w/o the electric shower?
    • CommentAuthorTimSmall
    • CommentTimeJun 14th 2012
     
    I've definitely used one (Triton?) which electronically modulates the amount of power supplied to the water, so this would probably work (i.e. the electric shower would just "top-up" as needed), but would probably be outside the manufacturer's warranty (not that they ever need know I suppose).

    There were two dials, if I remember correctly - temperature, and flow rate. This was in the North of Scotland in winter, and I remember that that you had to turn the flow rate right down in order for it to actually manage to reach the set point temp at it's max power input (a light flashed when it was below the set point).
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 14th 2012
     
    If you mix the 'cold' water to 23C which is within the range of mains water temperatures in the UK then you should not be doing anything that the shower cannot cope with or voiding any reasonable warranty, though you'd be bleeding the solar heat in very slowly, especially in summer when your cold mains is itself warm, perversely.

    Rgds

    Damon
    •  
      CommentAuthorfostertom
    • CommentTimeJun 14th 2012
     
    Posted By: TimSmallone (Triton?) which electronically modulates the amount of power supplied to the water
    Our Mira has Fast Medium and Slow buttons. Don't know about modulating - may just set one two or three elements manually.
    •  
      CommentAuthorJSHarris
    • CommentTimeJun 14th 2012
     
    I suspect it does depend very much on whether you have an ordinary electric shower or one that can somehow control the heating element power gradually depending on outlet water temperature (something I've not seen or heard of, TBH).

    We've had four electric showers over the years (before I fitted a combi boiler and plumbed in a mixer shower). All but the last one died after two or three years and I took each of them apart to see if they could be fixed. None had any form of power control to the element, other than the crude "temperature" dial switch that just selected one of two or three different power heating elements to use. All used water flow control to vary temperature, even the one with the "temperature" dial.

    My guess is that pre-heating water might allow you to reduce the power if you have a shower with a power control dial, but most probably you'd end up with just a higher flow rate shower.
    •  
      CommentAuthorfostertom
    • CommentTimeJun 14th 2012
     
    I'm pretty sure it does work - it's the payoff advertised for US/Can (not approved for UK) instantaneous shower waste water heat recovery units which pre-warm the incoming mains.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 14th 2012
     
    Give it a go and see what happens, has to be worth half a days plumbing.
    • CommentAuthortony
    • CommentTimeJun 14th 2012
     
    It will work
    •  
      CommentAuthorjoe90
    • CommentTimeJun 14th 2012
     
    JSH is dead right, the flow rate is altered to achieve the required temp, more expensive ones have low medium and high which are multi elements to give more heat to water. I have pondered this before (along with solar water for washing machines etc) and I have seen showers with "cold" option (made especially for Fostertom :bigsmile:) I recon with one of these and a mixer from solar and cold before the electric shower you could use the "cold" option for when your solar tank is topped up and either low,medium or high when you have partial heat, mixer to fine tune the temp. Simples.
    •  
      CommentAuthorfostertom
    • CommentTimeJun 14th 2012 edited
     
    Posted By: joe90showers with "cold" option (made especially for Fostertom)
    I swear by it! On Mira elect shower, simply turn the temp dial to lowest. I find mixer showers never go satisfactorily cold - nothing more deadening than tepid water!

    Can gauge the progression of the seasons, by incoming water temp.

    In olden days, trained men, whilst sitting in a special capsule on the boats's side, wd dangle their testicles in the water to gauge by its temp whether they were close to land or not. According to the Permaculture Bible.
    • CommentAuthorCWatters
    • CommentTimeJun 14th 2012 edited
     
    Perhaps one of these (with an add on pipe stat) feeding a thermostatic mixer would work...

    http://www.solaressence.co.uk/boilers/replacement-electric-boilers.html

    They are intended for heating stored hotwater so corrosion could be an issue if used as a "combi" feeding a shower (can't dose DHW with fernox).
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 14th 2012
     
    Posted By: fostertomIn olden days, trained men

    And what kind of training does the permaculture bibleoffer.
    How did we get to this:shocked:
  14.  
    Thanks for all of the inputs.

    The reason for using the electric shower is that it is in place and to replace it with a mixer would involve removing all the tiles so that the hot feed could be added then re-tiling.

    Our shower does have a cold setting so I will give it a go and report back my findings. I am just trying to use as mush solar hot water as possible (especially now we have a cold fill only washing machine!).

    Cheers Dave
    • CommentAuthorSeret
    • CommentTimeJun 15th 2012 edited
     
    If all else fails you could always just add a valve so you could manually switch between the electric shower (winter) and the solar hot water (summer).
    • CommentAuthordjh
    • CommentTimeJun 15th 2012
     
    Posted By: fostertomIn olden days, trained men, whilst sitting in a special capsule on the boats's side, wd dangle their testicles in the water to gauge by its temp whether they were close to land or not.

    Hmm, Pacific islanders in sailing canoes (proas) figure out where land is by watching what direction particular types of bird fly just before sunset. I know which technique I prefer ...
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 15th 2012
     
    You won't know until you've tried both...

    Rgds

    Damon
    • CommentAuthordelboy
    • CommentTimeJun 15th 2012
     
    With all this forum egging-on, you've got to give it a go! Put one in for the team etc.

    Let us know what happens - good luck!
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 15th 2012 edited
     
    Oh Buoy, it is going to hurt. I just been to look at the waves and can report that you coudl do this test just by sitting on the harbour wall.

    Or is it just a Transition Town/Permaculture trick to control population. Be up for a Darwin if it fails.

    It is hard to draw with a mouse when giggling.
      Tom.jpg
    • CommentAuthorTimSmall
    • CommentTimeJun 15th 2012
     
    Posted By: joe90JSH is dead right, the flow rate is altered to achieve the required temp, more expensive ones have low medium and high which are multi elements to give more heat to water.


    This is definitely the way that most of them work, but as I say, not all of them - I've used one (in my in-laws place on the North coast of Scotland) which has a temperature-controlled modulated output. You can hear it humming a bit at certain power levels...
    •  
      CommentAuthorDamonHD
    • CommentTimeJun 15th 2012
     
    Any tune that we could join in with on descant maybe? B^>

    Rgds

    Damon
    • CommentAuthorJoiner
    • CommentTimeJun 15th 2012
     
    Christ, Steamy! :shocked: Yours are detachable?????:shades: That's way cool.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 15th 2012
     
    My Mother removed them for save keeping until I grow up :bigsmile:

    But if your were hanging from yours, I think you may find they swell quite a bit, so big that the rest of me is hidden behind them.
    (if you want a laugh go look at my first abseil video in youtude, was a new harness and very tight)
  24.  
    Hi fostertom

    Would you recommend the testicle method when tracking down temperature drops on a solar hot water system? I can't see why it would not work and you would get sensitive measurements!

    Dave
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 17th 2012 edited
     
    I suspect that after a shower at 10°C it is hard to measure the diameter of a walnut, would require callipers and then is just getting perverse. Way to easy to drop the sensitive instruments when hands are soapy.
    • CommentAuthorGavin_A
    • CommentTimeJun 17th 2012
     
    we use this set up, but you need to actually use the mixer valve to set the temperature, then just run the electric shower on the cold setting, so its really just acting as a pumped shower.

    otherwise its thermostat can't really cope with heated water input.

    you need to make sure that guests understand this though.

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