Can you plumb hot water supply into an electric shower ?

dnme

Just wondering if you can plumb hot water supply into an electric shower ?

I have a Mira Elite St, during this cold weather, taking showers is miserable as it struggles to heat the extra cold water to a bearable temp. I often wondered if you could plumb the hot water supply into it.

I more or less have constant hot water here in the tank from using the central heating. If I could plumb the hot water supply into my shower, it would have to far less work to heat the water during showers, thus making it cheaper, more efficient, warmer showers etc.

Any thoughts?

Joey the lips

Firstly to answer your question..... No!

Your theory is not sound and actually dangerous.

As the mira elite is not thermostatic in theory you can scald yourself or others quite easy.


However if you have that constant supply of hot water then perhaps you should switch your mira elite to a power shower...

mullingar

+1 on what Joey said ^^

A domestic hot water supply can often reach 50C+, so ask yourself how are you going to cool that water??

Buy a new MIXER shower if you want to use the existing HW

dnme

Thanks guys,

I guess what I was really after was having the best of all worlds. So ideally, plumbing the hot and cold water into the power shower. That way it's never too hot, you are getting the benefit of the existing hot water and saving money. AND in the summer you don't have to pre-heat water before your shower.

I mean, surely there's a smart mixer valve that can handle this. If I turn it to cold, it gives me the cold feed. If I turn it up to hot, it gives me the hot feed plus and power it needs to add the extra required heat.

It just kills me the inefficiency of it all. Anyway I take your points and many thanks.

Joey the lips

dnme wrote: »

Thanks guys,
I mean, surely there's a smart mixer valve that can handle this. If I turn it to cold, it gives me the cold feed. If I turn it up to hot, it gives me the hot feed plus and power it needs to add the extra required heat.

It just kills me the inefficiency of it all. Anyway I take your points and many thanks.

In the words of the late lesley neilson... Dont call me shirley.....

It all depends what you want to do.

There are many showers for many things but not one shower for everything...

You want a shower that can

Pump the water

Heat the water

Control the temperature

at a fast rate..

The best solution out there is actually what you have but its working slower because the temp needs to be raised higher....

heinbloed

The max. allowed feed-in temperature can be got from the installation manual. Usually around 20 degrees Celsius for most makes, a no-brainer to install a mixing valve between shower and DHW source....


There are many electric showers nowadays available which are designed to take warm/hot water.
Check the www. for your " favorite brand plus solar".

Mira has one of these 'solar' showers as well, you can get it at most Irish plumbing centers. See their home page for further technical details.

Joey the lips

heinbloed wrote: »

The max. allowed feed-in temperature can be got from the installation manual. Usually around 20 degrees Celsius for most makes, a no-brainer to install a mixing valve between shower and DHW source....


There are many electric showers nowadays available which are designed to take warm/hot water.
Check the www. for your " favorite brand plus solar".

Mira has one of these 'solar' showers as well, you can get it at most Irish plumbing centers. See their home page for further technical details.

I would be wery of using a blending valve on a pumped shower.. The reduction in water flow that occurs with them would not be healthy for the shower...

However the idea sounds interesting... It could actually reduce energy consumption if it was a workable idea.

groodyman

I just tried this today. Supplied my electric Triton T90si 8.5 KW from my hot water cylinder. Took 10 minutes to switch the pipes over.

I then was able to run the shower at maximum pressure and a reduced heater setting. Worked a treat. You can adjust the heater setting depending on the water temprature in the cylinder. If the cylinder water is hot enough the the electric shower heater setting can be set to cold and you still get max pressure showering with the temprature of the water in the cylinder.

The trick here is to set your cylinder thermostat so that it will not to heat the water hot. Just luke warm.
(Remember the electric shower cannot cool water)

I have mine on a daily timer. Heats the cylinder water for 30 mins every 24 hours. This keeps the cylinder water luke warm.

Now I have full pressure from my electric shower even in very cold weather. And I'm using less power to run the electric shower.

Dtp1979

groodyman wrote: »

I just tried this today. Supplied my electric Triton T90si 8.5 KW from my hot water cylinder. Took 10 minutes to switch the pipes over.

I then was able to run the shower at maximum pressure and a reduced heater setting. Worked a treat. You can adjust the heater setting depending on the water temprature in the cylinder. If the cylinder water is hot enough the the electric shower heater setting can be set to cold and you still get max pressure showering with the temprature of the water in the cylinder.

The trick here is to set your cylinder thermostat so that it will not to heat the water hot. Just luke warm.
(Remember the electric shower cannot cool water)

I have mine on a daily timer. Heats the cylinder water for 30 mins every 24 hours. This keeps the cylinder water luke warm.

Now I have full pressure from my electric shower even in very cold weather. And I'm using less power to run the electric shower.

Nice idea but heating your water in your cylinder to "warm" is very dangerous. Google legionaries disease.
You MUST heat stored hot water to a minimum 55 degrees Celsius

groodyman

groodyman wrote: »

I just tried this today. Supplied my electric Triton T90si 8.5 KW from my hot water cylinder. Took 10 minutes to switch the pipes over.

I then was able to run the shower at maximum pressure and a reduced heater setting. Worked a treat. You can adjust the heater setting depending on the water temprature in the cylinder. If the cylinder water is hot enough the the electric shower heater setting can be set to cold and you still get max pressure showering with the temprature of the water in the cylinder.

The trick here is to set your cylinder thermostat so that it will not to heat the water hot. Just luke warm.
(Remember the electric shower cannot cool water)

I have mine on a daily timer. Heats the cylinder water for 30 mins every 24 hours. This keeps the cylinder water luke warm.

Now I have full pressure from my electric shower even in very cold weather. And I'm using less power to run the electric shower.

There was a fella I came across who wanted 100% efficiency out of his living room gas fire so he ran a rubber hose into the middle of the room pushed a bit of copper in the end and propped it up on bricks, the other end he taped to a gas pipe, turned on the gas and lit it.

So I say to you what I said to him "yes I know it can be made to work but there are much safer ways of doing it".

Now admittedly he was unconscious and was on his way to hospital so I didn't get a reply:(

groodyman

I've been keeping the cylinder water just luke warm for years, don't need it really hot. Still no sign of legionaries disease.

The electric shower is no longer an annoying bare trickle in the cold weather.

So instead of installing an expensive mixer system with a seperate pump and using heaps of energy keeping the cylinder water very hot. I had just 10 minutes work swapping over a pipe and no cost at all.

Took a chance, it worked. I'm happy.

Dtp1979

groodyman wrote: »

I've been keeping the cylinder water just luke warm for years, don't need it really hot. Still no sign of legionaries disease.

The electric shower is no longer an annoying bare trickle in the cold weather.

So instead of installing an expensive mixer system with a seperate pump and using heaps of energy keeping the cylinder water very hot. I had just 10 minutes work swapping over a pipe and no cost at all.

Took a chance, it worked. I'm happy.

Let's hope somebody you love doesn't die from your stupidity.

The Sidewards Man

Dtp1979 wrote: »

Let's hope somebody you love doesn't die from your stupidity.

Shot fired.

groodyman

It's all fun and games until someone loses an eye.

Or suffers death by lukewarm water.

The Sidewards Man

Them lukewarm molecules of water are ferocious for sure.

Dtp1979

groodyman wrote: »

It's all fun and games until someone loses an eye.

Or suffers death by lukewarm water.

Or suffers death by water heated to less than 55 degrees, therefore potentially creating deadly bacteria to form which mostly leads to fatalities when the water vapour is inhaled, which is mostly from showers.

The Sidewards Man

Dtp1979 wrote: »

Or suffers death by water heated to less than 55 degrees, therefore potentially creating deadly bacteria to form which mostly leads to fatalities when the water vapour is inhaled, which is mostly from showers.

Have you links or some vague back up to this Halloween myth?

Dtp1979

The Sidewards Man wrote: »

Have you links or some vague back up to this Halloween myth?

http://www.nejm.org/doi/pdf/10.1056/NEJM197712012972202
http://cmr.asm.org/content/15/3/506.short

Dtp1979

http://cmr.asm.org/content/15/3/506.short

The Sidewards Man

That link is useless, I do not doubt that legionnaires disease exists, I want to know how many die in Ireland in showers from it.

The Sidewards Man

Second link equally useless.

The Sidewards Man

The Sidewards Man wrote: »

Have you links or some vague back up to this Halloween myth?

Why would you think it was made up?? is it just easier to think that those with experience Have been misinformed all there working lives.

mickdw

Is idiotic to scoff at this.
Good advice has been given and it is true that it is in showers that the biggest danger arises.
Anyway heating cylinder for 30 mins and storing a volume of water all day sounds inefficient compared to having the shower heat the water.

The Sidewards Man

Experience at what exactly, making up fairy tales of people dropping dead in the shower is it?

The Sidewards Man

The Sidewards Man wrote: »

That link is useless, I do not doubt that legionnaires disease exists, I want to know how many die in Ireland in showers from it.

There is a big debate in the UK at the moment (and I could see you being a great chairman) over the number of people dying from legionnaires vs those the number of people dying from scalding incidents, so because more people are at the moment being scalded some want to reduced the sitting temperature of stored hot water to lower temperature of 50c Ish.

Personally I'd heat the water to 60c then put a blending valve on the cylinder so nobody has to die, but what do I know.

Wearb

How many people die from electrocution every year. Not many. Because there are safeguards in place. Same with Legionares. People aren't dying with it because all good plumbing setups guard against it.

It's not common, but do you want a member if your family to be the exception.

The Sidewards Man

Gary how many in the Uk die every year form legionnaires? Bringing the scalding water is irrelevant and confusing.

The Sidewards Man

The Sidewards Man wrote: »

Experience at what exactly, making up fairy tales of people dropping dead in the shower is it?

I can act a a bit of a fairy at times but I don't tell tales.

I'm more than happy for you to shower in what ever temperture of water you wish as I do believe in natural selection, it's my job only to give you the information if you don't wish to except that then that ain't my problem.

Dtp1979

The Sidewards Man wrote: »

Second link equally useless.

http://www.nhs.uk/conditions/Legionnaires-disease/Pages/Introduction.aspx

dazed+confused

The Sidewards Man wrote:

That link is useless, I do not doubt that legionnaires disease exists, I want to know how many die in Ireland in showers from it.

There has never been a recorded death from legionnaires disease that was contracted in a domestic building.

It has happened in hospitals, care homes, municipal buildings etc.

Dtp1979

dazed+confused wrote: »

There has never been a recorded death from legionnaires disease that was contracted in a domestic building.

It has happened in hospitals, care homes, municipal buildings etc.

Link?

The Sidewards Man

The Sidewards Man wrote: »

Gary how many in the Uk die every year form legionnaires? Bringing the scalding water is irrelevant and confusing.

I don't think it is, for me as a heating engineer it's the two things that have the biggest impact on a home owner when hot water design is looked at, its also something the industry is looking at right now with some arguing similar points to yourself.

But as for deaths there would be none at all at all from legionnaires if fairies like me were listened to also Irish homes are at greater risk than UK homes as hot water cylinders (up until the SEI grants scheme anyway) commonly had no basic controls for temperature allowing a greater risk of legionella and scolding amongst the young and old.

There is a bit of info below (I don't have numbers personally) but again if you no wana listen that's OK.


large buildings, such as hotels, hospitals, museums and office blocks, are more vulnerable to Legionella contamination because they have larger, more complex water supply systems in which the bacteria can quickly spread.
The two things that Legionella bacteria need to grow and reproduce are:
a water temperature of 20-45C (68-113F)
impurities in the water that the bacteria can use for food – such as rust, algae and limescale
Although rare, Legionnaires' disease has also come from contaminated showers, sprinkler systems and spas.
Legionnaires' disease is rare in the UK. In 2013, 284 people were reported to have the infection in England and Wales. Of these cases, 88 people (31%) were exposed to the infection while travelling abroad – mainly to Mediterranean countries, but also tropical countries such as India. However, given the millions of trips made abroad each year, 88 cases is a very small number.
Cases of Legionnaires' disease arising in England and Wales usually peak between July and September.
Increased risk
Everyone is potentially at risk of developing Legionnaires’ disease. However, certain things make it more likely that you will experience a more severe form of the infection. These include:
being 50 years of age or over – 235 (83%) of the 284 confirmed cases in 2013 involved people over 50 years of age
smoking, or having smoked heavily in the past (a recent study has shown that smoking cannabis may also increase your risk)
drinking alcohol heavily
about three-quarters have an underlying medical condition, such as diabetes, kidney disease, or a pre-existing lung condition
having a weakened immune system – for example, people with HIV and AIDS or cancer

evolving_doors

dazed+confused wrote: »

There has never been a recorded death from legionnaires disease that was contracted in a domestic building.

It has happened in hospitals, care homes, municipal buildings etc.

There aren't recorded deaths for lots of unsafe things, but that doesn't make the unsafe thing safe.

I think if you are looking for statistics then probably your safest bet would be to ask what are the 'chances' of creating legionnaire's in a certain environment. Going by the NHS info:

The two things that Legionella bacteria need to grow and reproduce are:

1. A water temperature of 20-45C (68-113F)
2. Impurities in the water that the bacteria can use for food – such as rust, algae and limescale.

So we'll assume that the OP has fulfilled criteria 1. then I suppose the next thing to assess is the chances of having rust,algae or limescale present in a heating system.

I'm not a plumber by any means (no means really) so I suppose the only thing to do is ask any plumbers here if they have ever come across rust,algae or limescale in pipework?

The Sidewards Man

This argument is weak also the posters who are constantly blowing of their profession thinking they are more qualified than other posters is puerile.

The Sidewards Man

The Sidewards Man wrote: »

This argument is weak also the posters who are constantly blowing of their profession thinking they are more qualified than other posters is puerile.

But I am more qualified ??? It's what I do for a living, my nephew plays professional rugby I don't tell him how to catch a ball because I've been watching rugby on the telly for 30 years, that would be really silly and he'd punch me:(


It's very very easy to have a opinion when it cost you nothing but when you are working in people's homes like I am taking any risks is not a option even if those risks are perceived to be utter nonsense by those who think they have a better handle on things.

groodyman

The thread is whether you can run an electric shower from a hot water supply or not.

The answer is yes. With the risk of scalding if the cylinder temperature is set too hot and "apparently" the minute possibility of legionaries disease.

So it's up to the electric shower owner. If they want to bare the risk for the good powerful shower spray.

I think it is something that can work well for personal preference in a private residence where it can be managed, but not for installation guidelines.

evolving_doors

groodyman wrote: »

The thread is whether you can run an electric shower from a hot water supply or not.

The answer is yes. With the risk of scalding if the cylinder temperature is set too hot and "apparently" the minute possibility of legionaries disease.

So it's up to the electric shower owner. If they want to bare the risk for the good powerful shower spray.

I think it is something that can work well for personal preference in a private residence where it can be managed, but not for installation guidelines.

Don't forget the legionnaire's risk.

The Sidewards Man

gary71 wrote: »

But I am more qualified ???

As a real engineer are you an actual real one or one of those ones that do a 3 week course and become one of these rgi or Uk equivalent?

The Sidewards Man

The Sidewards Man wrote: »

As a real engineer are you an actual real one or one of those ones that do a 3 week course and become one of these rgi or Uk equivalent?

What difference would that make to you, the information posted is enough to determine there is a risk.

Your opinions on connecting a shower in the manor mentioned as posted show you don't have experience of things that can go wrong, it's the things that go wrong that tend to teach the most and this is factored in to the opinion of those with more experience but very hard to explain to those who don't.

But to answer your question I am a time served City and Guilds qualified emergency gas service engineer, it was a 4 year apprenticeship, I have worked in the industry for nearly 30 years and the last 12 years I've worked as a boiler manufacturers technical adviser identifying defects with heating and hot water systems across the country, I hope this helps but if not I can still teach you how to throw a rugby ball;) it's all in the wrist.

Wearb

@The Sidewards Man

Do you agree that the risk exists?

If yes, then it seems that you think that it's small enough to take that risk.

Then, after reading this thread, you have more information to help you make that decision.

Because I am not a doctor, I can advise you to take a few paracetamol if you have a pain and suffer no repercussions if you die afterwards. But if I were a doctor, I would be subject to an investigation, because I should have known better.

Same applies here, when you read advice from professionals. The advice has to be best practice. We cannot say it's ok, just because very few die from it.

You have gotten good advice and now it's up to you what you do with it.

Most importantly for me; anybody reading this thread, will realise that there are risks assiocatiatedd with connecting a showere that way.

The Sidewards Man

gary71 wrote: »

Your opinions on connecting a shower in the manor mentioned as posted show you don't have experience of things that can go wrong, it's the things that go wrong that tend to teach the most and this is factored in to the opinion of those with more experience but very hard to explain to those who don't.

I have not expressed any opinion on connecting a shower in this thread did I get the winky eye right?
Look up the definition of engineer

The Sidewards Man

Wearb seemingly you need to be some sort of an engineer to make your point valid, Gary has made this clear.

The Sidewards Man

The Sidewards Man wrote: »

I have not expressed any opinion on connecting a shower in this thread did I get the winky eye right?
Look up the definition of engineer

I never said I was good;) I'm not a engineer I'm a service engineer it's what is written on my City and Guilds cert;)

Please feel free to contact British Gas if you wish as they are responsible for the terminology.

anothernight

The Sidewards Man wrote: »

As a real engineer are you an actual real one or one of those ones that do a 3 week course and become one of these rgi or Uk equivalent?

For what it's worth, I'm a "real engineer"... with no practical knowledge about any of this stuff.

The Sidewards Man

The Sidewards Man wrote: »

Wearb seemingly you need to be some sort of an engineer to make your point valid, Gary has made this clear.

Now your being silly, yes I am qualified as are others who have posted on this thread, as someone who is still learning my trade I don't put myself over anybody.
.

I don't think any experienced plumbing poster is going to agree that this type of installation is a very good idea but why should that be such a hard thing to get across?

Guy:Incognito

groodyman wrote: »

I think it is something that can work well for personal preference in a private residence where it can be managed, but not for installation guidelines.

And how is the private home owner "managing" the situation? Are they inspecting the internals of the heating system? How are they ensuring the accuracy of the water temperature? are they even doing basic things like cleaning the shower head regularly?

Dtp1979

Guy:Incognito wrote: »

And how is the private home owner "managing" the situation? Are they inspecting the internals of the heating system? How are they ensuring the accuracy of the water temperature? are they even doing basic things like cleaning the shower head regularly?

No, they have a cylinder thermostat set to 60 so when the water reaches 60, it stop the cylinder becoming hotter

Guy:Incognito

Dtp1979 wrote: »

No, they have a cylinder thermostat set to 60 so when the water reaches 60, it stop the cylinder becoming hotter

Ah yes, the "fit and forget" the most basic of criteria for some safety form of managing. What could possibly go wrong.

Dtp1979

Guy:Incognito wrote: »

Ah yes, the "fit and forget" the most basic of criteria for some safety form of managing. What could possibly go wrong.

It's better than some fool willingly under heating the water, knowing the risk they pose to themselves and other family members

K.Flyer

My biggest concern would be if your immersion element thermostat failed, and they very often do, and the temperature of the stored water was to rise to a dangerous level.
The person using the shower would be unaware of this danger as they would be at first receiving hot water produced by the shower unit itself and heating the water from the pipe-run.
Then the potentially scalding water will arrive at the shower unit and if you are in a shower enclosure, say with your back to the shower unit, those seconds it takes for you to register what is happening and to turn around and reach through the excessively high water temperature to turn off the unit or to direct the shower head away, could be enough time for damage to be done.
Now what if this was to happen to a younger person, or an older person when using the shower, whose reactions are not quite as fast as yours, is it really worth the risk?
This is why there is no instructions in the installation booklet that suggests connecting the water supply to a pre heated water source, because you are now by-passing the safety feature built into the shower unit.

Walter Becket

I have done this and it works well. A short pipe run from the cylinder is essential. Care must be taken when setting the thermostatic mixing value. I done it with a triton t90 using a 1/2" thermostatic mixing valve. The shower is on a wall backing onto the hot press, the feed pipe to the hot cylinder is 1" so is the cold feed pipe and generally the pipes are oversized. The thermostatic mixing value takes care of unpredictable water temperature from the hot cylinder. When using any shower the user should let the water flow for a while to allow the temperature to stabilise before getting in the shower and when you think about it this is what we all do automatically. Once the pipe run from the cylinder is short the temperature will stabilise quickly. The risk with this idea is that with a long pipe run from the cylinder the user may think the water temperature has stabilised when in fact warm water hasn't got to the shower from the cylinder yet. The risk of legionnaires is not increased because water is not stored warm. Proceed at your own risk remember this is breaking the rules.