WARNING-Solar geysers could pop!




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  1. #1
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    Exclamation WARNING-Solar geysers could pop!

    A heads up on solar geysers and water restrictions/ pressure reductions.....

    http://www.news24.com/SouthAfrica/Ne...plode-20171012

    Cape Town Water outages to preselected suburbs by the City of Cape Town could lead to solar water geysers "exploding", an electrical and electronic engineer warned on Thursday.
    The City on Monday announced that Phase One of its Critical Water Shortages Disaster Plan came into effect which would cause water outages during peak water usage periods in the mornings and evenings.
    Residents would be informed before water outages occur.
    Professor Thinus Booysen from Stellenbosch University's electrical and electronic engineering department said solar water geysers is dependent on cold water to regulate temperatures.
    He said if water in the panel becomes too hot, or pressure too high, the safety valve opens which replaces hot water with cold water.
    "In the event of a water outage, no cold water will replace the hot water, which could lead to overheating, and which could result in scalding (when hot water is used and it is beyond 100 degrees Celsius), and the solar system possibly stalling, which in turn could lead to explosions," Booysen told News24.
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  2. #2
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    Default Re: WARNING-Solar geysers could pop!

    uhm ja ....

    panel overheats ... causes STEAM, causes increase in pressure, safety valve opens and pressure is released ....


    The element could burn out !! With no water in the geyser the thermostat wont measure "hot water" and the element could stay on for the periods of the timer.


    The excessive temperatures DO lead to premature failure of some components !! We have seen this on many installations.


    but a geyser "exploding" ..... NOT while the pressure relieve valve works.

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  4. #3
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    Default Re: WARNING-Solar geysers could pop!

    My system's PRV works fine. On hot, sunny days there is an occasional trickle of water from the overflow that is directed to a handy 25l container, and thence, to do duty as car window washing and general usage water.
    Cheers,
    John

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  5. #4
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    Default Re: WARNING-Solar geysers could pop!

    Yip, it will happen. My FIL had a few go pop on the farm when water was depleted and then cold water back in again in the sun. He lost quite a few tubes over the years.

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  6. #5
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    Default Re: WARNING-Solar geysers could pop!

    Quote Originally Posted by Dave Faddel View Post
    Yip, it will happen. My FIL had a few go pop on the farm when water was depleted and then cold water back in again in the sun. He lost quite a few tubes over the years.

    Aaaahhh ....

    YES, the evacuated tubes HATES this !!


    The geyser itself wont pop though. (at least, it should NOT)


    That said .... when cold water enters the panel, even a solid panel, the water boils of instantaneously !!! the rapid steam generation could cause damage ..... IF the system can create any airlocks (bad pipe layout) this rapid steam generation could then lead to damage.


    Part of the installation methodology is to cover the panel until the system is filled with water, for this very reason.



    would be interesting to see if any systems do "pop" .....

  7. #6
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    Default Re: WARNING-Solar geysers could pop!

    There will always be water covering the element. The hot water comes out of the top via pressure.
    If you stop the cold water from entering the HWC, the pressure will also stop, preventing more hot water to escape.
    HWC"s cant explode, but burst they can, especially if the safety valve is faulty.

    Today's technology, i cant see the current stuff exploding. Engineers would have taken into account the lack of no water situation.
    I also understand that there is also a pressure release valve on the solar panel installation. could be the latest ones.


    ORA
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    Ian

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  9. #7
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    Default Re: WARNING-Solar geysers could pop!

    Interesting scenario.I dont do solar but have dabbled with some. Geysers can explode. You just need to try hard enough.All you need is for some clown to forget to put a pressure reducing valve on the system. Then he just needs to put a vacuum breaker on the tp valve. Dont laugh, Ive come across a few in my life. Then you just need a scenario where the thermostat packs up and BOOM:
    Or if they install a pressure reducing valve but have a stopcock between the geyser and pressure reducing valve and close it.

    To all the Cape Town residents. If your water is going to be cut I suggest putting timers on your geysers so you can ensure the power is off to your geyser during water outages. This applies to solar and conventional.
    In Umdloti during water outages last year I would have to replace many elements on geysers because the hot water drained out.
    If you want to prevent this make sure your anti syphon systems are in place and working.
    Make sure your vacuum breakers are kicking in. Or install a non return valve but make sure you know what you are doing. It would pay to spend twice as much and buy a good quality cobra vacuum breaker instead of a kwikot vacuum breaker.The kwikot ones tend to jam over a period of a few months.

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