Astra
Full Member
Posts: 219 
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Post by Astra on Aug 2, 2020 14:11:51 GMT
Can anyone offer any reason why this happens  We have an issue with our shower. When the weather gets too warm there is no pressure from the shower and we struggle to use it. Would it be because of the added temperature and the more demand for water at that time in the local Area ?? Many thanks in advance for your time Guy's |
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Post by battle1066 on Aug 2, 2020 18:29:27 GMT
Can anyone offer any reason why this happens We have an issue with our shower. When the weather gets too warm there is no pressure from the shower and we struggle to use it. Would it be because of the added temperature and the more demand for water at that time in the local Area ?? Many thanks in advance for your time Guy's Worth reading this www.showerspares.com/blog/seasonal-effects-on-electric-showersAs as the latter part deals with summer problem and a simple suggestion as a cure. |
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Post by crowsfoot on Aug 2, 2020 19:53:48 GMT
Winters cold snap is when we get the electric shower problems.
When the incoming mains feed can be as low as a couple of degrees.
Summertime is generally when electric showers give their peak performance so I'd say that you're on the mark Astra with a high demand of supply on the water main being the cause.
There's an old rule of thumb with electric shower which is to turn the wash basin tap on full and watch the flow of water from it then whilst still watching the flow get someone to flush the WC - keep watching that flow of water from the tap and if you notice a reduction in the flow of water from the basin tap whilst the WC is filling then you can determine that the shower is not getting enough flow of water to work properly.
Check that a full bore isolation valve's been fitted on the shower feed too, it's surprising how much ristriction there is on a normal non FB iso' valve.
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Post by dickpuller on Aug 2, 2020 20:14:41 GMT
I agree with CF, limited flow rate can be a big problem with leccy showers. What you must appreciated is to heat the water, the flow rate through the shower is already limited. Also the shower rating will have a big bearing on this too.
I’ll demonstrate the Mass Flow Rate & relationship to shower KW input later, you’ll understand the concept better.
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Post by tomplum on Aug 2, 2020 20:49:50 GMT
I also agree with Tappy and dick, an electric shower will work well in Summer but, it needs a good supply of water as well, if the pressure is low and then you are using it at peak times, the problems will happen, the cutout devices will kick in to protect the heat exchanger,  |
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Post by dickpuller on Aug 3, 2020 19:34:32 GMT
Here’s a video that explains electric showers fairly well. Notice how he says a 7.5KW Shower will only give you 3Ltr/min at 40degree C in the Winter.
So roughly how do we know what we’ll get from a particular KW size of shower?
3Ltr/min is 0.05Ltr/sec......OK 3 divided by 60 = 0.05.
To rise the water temperature to 40degree C with an incoming mains temperature of say 10degrees C, means you increase the temperature by 30degrees C. 30degree C temperature rise or a Delta T of 30degrees C.
Our Delta T is 30 we multiply that by 4.2(this is the specific heat of water) = 126
We take our 0.05Ltr/sec multiply it by 126 = 6.3KW
That maybe help explain the relationship between the shower KW rating & the flow rate from the shower.
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