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Bad Advice? Water Heater.

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"Due to their point-of-use installation these units also benefit from minimal standing heat loss, and when added to the fact that, because this heater is only 3kW, unlike instantaneous water heaters, it can be spurred off a ring main rather than requiring its own dedicated circuit and then it becomes clear why the Redring WS7 Water Heater has quickly become a firm favourite."



Outlet Spout: 300mm


Is this really sensible advice. Years ago we put 3kW immersion heaters on a dedicated radial circuit. Is this advice a backwards step?


Z.


  • 0
    Seems like that is a bit of a mistake in certain circumstances  ie oven kettle and a water heater you'd soon be over your 32 amp limit. Think it needs caution in instalation good job we know what we're doing
  • 0
    A small (in water capacity, not in electrical loading) water heater may in my view be connected to a ring final circuit. It is arguably no worse than an electric kettle that might otherwise be used to provide the same hot water demand.


    There are several types of point of use 3 kw water heater.

    Some have no storage whatsoever, rather like an electric shower. The flow rate of these is minimal, OK for handwashing but not very good for washing up.


    Other types have a small storage vessel, these are a better product in my view. The flow rate will fill a washing up bowl or small sink quickly, and re-heat in about 10 or 15 minutes if more hot water is desired.


    Some types have a pressure rated storage vessel, these can be installed under the sink with the outlet connected to a standard tap. These MUST be correctly installed as they are a pressure system. They can explode if defective or incorrectly installed.


    Other types have a non-pressure vessel, which is permanently connected to an open outlet spout. To obtain hot water, a COLD WATER inlet valve is opened and this displaces the hot water. These are cheap, safe, and simple but are now VERY last century.
  • 0
    Oven, water heater and tumble dryer maybe more of a problem. The 2 minute flash to 40 amps on a 32A breaker to make a cup of tea will not trip anything or overheat the wiring .

    Not sure why your oven is on the ring for that matter..

    Realise that the original ring designers also assumed you'd be lugging electric fires from room to room, instead of setting up the fireplace, now with central heating you probably do not. 

    Also being only 7 litres the re-heat time with a 3kw element will not be much more than quarter of an hour or so anyway, so not like a 200 litre tank all night.

    (to raise one litre of water 1 degrees is 4.2 kw seconds, or 1.5 seconds per degree.litre at 3kW , and I presume you do not want it boiled more like a 40- 50 degree rise,  so 50deg *1.5* 7litre = 525seconds, ~10mins  )

    It is probably OK, but it rather goes against the current trend for fitting  lots of radials one per major load.

    Mike

  • 0
    The original design for socket ring circuit allowed for two 3 kW point loads, this is one 3 kW point load so the circuit can accommodate another one as well.
  • 0
    how many KW were the old common creda corvette?
  • 0
    mapj1:

    Not sure why your oven is on the ring for that matter..


     


    Single ovens come with 13A plugs on them these days.


  • 0
    ebee:

    how many KW were the old common creda corvette?


    2 kw IIRC.


  • 0
    Sparkingchip:

    The original design for socket ring circuit allowed for two 3 kW point loads, this is one 3 kW point load so the circuit can accommodate another one as well.


    Indeed, and in practice more than two loads each of 3 kw can be used if these are short term.


    Washing machine, kettle, toaster, microwave, and oven for example will in practice be fine. The washing machine will only use full power for about ten minutes whilst heating the water, much less for the rest of the cycle. Kettle is unlikely to be used for more than five minutes. toaster is also short term and often only 6 amps, microwave 8 amps at the most and also short term. Conventional oven is potentially on for an hour more.


  • 0
    Simon Barker:
    mapj1:

    Not sure why your oven is on the ring for that matter..


     


    Single ovens come with 13A plugs on them these days.




    That's so that they can be plugged into the cooker control panel's 13 Amp socket.?


    Z.


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