Feed to electric shower?

mikeymouse

First fix plumbing and electrics being done in new extension.
When talking to electrician while doing cables for new downstairs electric shower ,
he asked about chasing for water feed to new shower.
I said it would come from the main house supply; a bored well with a surface pump,
through a new filtering system and before going to the new boiler (not a combi boiler).
He said it should come directly from tank in loft.
This means running it through the house ,not ideal as newly decorated.
There is a fluctuation in the water pressure when the pump kicks in ,
So my question to you guys is, would a thermostatic electric shower
fed from the mains, directly after the filtering system work?
Or will I have to take the feed from the tank in the loft.
Plumber away for a couple of weeks and I want to have shower ready for him when he gets back.

Sleeper12

If it were a city build relying on mains pressure I'd agree with him. I'm actually a bit impressed with an electrician thinking along these lines when many plumbers connect to the mains rather than the tank because it's easier for a downstairs shower.

If the supply feeding the shower is pumped then you should connect a mains fed shower like triton t80z or a mira sport. The pump will keep the pressure constant. In your situation the best option not from the attic

4ensic15

I would always feed an electric shower from the loft tank. It should be on a line of its own. The water pressure will be constant and there is no danger of other draws on the supply. Anything else is just crap.

g6fdyotp5nj2l7

Am I missing something here I was of the impression all electric showers are mains fed

4ensic15

Kason Howling Manager wrote: »

Am I missing something here I was of the impression all electric showers are mains fed

Not all electric showers are mains fed. All the Triton t90's for example are, and must be, tank fed. I would not put in a mains fed electric shower. Any I have ever used gave an unsatisfactory shower and were a nuisance. For the sake of the extra few euro, it is better to use a tank fed shower, particularly if the shower is going to be used frequently.

Sleeper12

Kason Howling Manager wrote:

Am I missing something here I was of the impression all electric showers are mains fed

Tank fed (best suited for Ireland) have built in pumps.

Mains fed rely on the mains pressure and don't have pumps. The only way we ever install a mains fed shower is if it's on a pump. There are probably 25 to 30 pumped electric showers in Dublin for every 1 mains fed shower. The mains pressure in most of Dublin isn't good enough for a mains fed shower

g6fdyotp5nj2l7

Thanks for the replies. There's a mains fed electric shower in the house I'm in at present and it's a pain. Especially in winter when it's hot enough the flow is very poor.
Would a tank fed one be a better option.

4ensic15

Kason Howling Manager wrote: »

Thanks for the replies. There's a mains fed electric shower in the house I'm in at present and it's a pain. Especially in winter when it's hot enough the flow is very poor.
Would a tank fed one be a better option.

It depends on the power rating. Some are 8.kw and others are 9.0. and so on. The other factor is the tempreature of the water in the tank. In winter mains water is cold and most of the pwer is used heating it up from a low temperature hence the poor flow rate. If the attic is warm the water will be warmer and less power will be consumed heating up the water and so a better flow rate can be maintained.
Chaning over from mains fed may involve electrical as well as plumbing work.

Sleeper12

Kason Howling Manager wrote:

Thanks for the replies. There's a mains fed electric shower in the house I'm in at present and it's a pain. Especially in winter when it's hot enough the flow is very poor. Would a tank fed one be a better option.

A tank fed shower has a pump and can pump out up to 10 litres of cold water. The advantage of the pump is to give constant pressure so the shower will always provide hot water. A mains fed shower may not be able to provide hot water at peak times & the water will go hot and cold if someone runs the cold water at the kitchen sink.

Pumped electric and mains electric provide the same pressure but mains might fluctuate. The standard electric shower is now 9kw and the most powerful is 10kw You can increase the KW of the shower but in most cases you will need to rewire to do this & the benefit is only around 10 percent more pressure. 3 litres per minute on a cold winters day increased to 3.3 or 3.4 litres isn't life altering. You won't notice 10 percent increase most of the time.

g6fdyotp5nj2l7

So what ye're saying is that a tank fed electric shower will be a marginal improvement at best in the winter.
Bearing in mind that the mains pressure is good where I am and as the attic is well insulated I don't expect the water in the tank to be very warm in winter.

Sleeper12

Kason Howling Manager wrote:

So what ye're saying is that a tank fed electric shower will be a marginal improvement at best in the winter. Bearing in mind that the mains pressure is good where I am and as the attic is well insulated I don't expect the water in the tank to be very warm in winter.

No. A tank fed shower will be no improvement at all. If you have good pressure then a tank fed shower is no better than a mains fed shower. Both preform the same as each other in winter and summer. On courses in the Triton factory in the UK none of the plumbers have ever heard of a Triton t90 or have any experience of a Pumped electric shower. In the UK they have great mains pressure so they don't have t90 showers. They all have mains fed showers.

The only thing that can boost your pressure is to increase the KW of the shower. 9KW is now the industry standard in Ireland but there are 10kw. The extra pressure is minimal though. I've had clients go from 9 to 10kw and not be happy. Some insist there was no increase in the pressure. Not many people will notice 10 percent increase in pressure. The older Triton t90 showers were 8.5kw. We replace them with 9kw t90 showers and many homeowners actually believe that they are getting less pressure & not more. This isn't the case of course but it shows how you won't really be able to tell the difference

4ensic15

Kason Howling Manager wrote: »

So what ye're saying is that a tank fed electric shower will be a marginal improvement at best in the winter.
Bearing in mind that the mains pressure is good where I am and as the attic is well insulated I don't expect the water in the tank to be very warm in winter.

The water in you attic will be a lot warmer than mains water in winter. You should not be insulating under the tank. The power rating kw does not refer directly to water pressure but to the electric power heating the water. In an electric shower there is a constant level of power so the only way to contral the heat of the water is by reducing the flow to increase heat or increasing the flow to reduce heat.
Because of other factors, principally the variation in the heat of the water in the tank it can be difficult for people to notice a change in power but in winter the old 9.5 tritons were better than the 8.5.

John.G

Assuming the same showering temperature, a 10 kw mains fed shower will certainly match or better the flow rate from a tank fed (higher supply temperature) 9 kw shower. As the OP is installing new electrics I would certainly consider the 10 kw mains fed one. The supply voltage also has a considerable effect on the shower output, I have a 9 kw mains fed shower but because the supply voltage is always > 240V (a measured 236V at the running shower terminals) I have in effect a almost 9.5 kw shower, others are not so fortunate, my relations in the country have the exact same shower with a measured 223V at the shower terminals so in effect = a 8.5 kw shower and I certainly notice it when showering. If they had a 10 kw shower then it would effectively be a 9.4 kw shower.
I know that one has to accept the supplied voltage but in a new install then the 10 kw shower??, (mains OR tank fed)

Sleeper12

I agree with John. 10kw mains shower, going through the pump, if it's a new installation. The if its tank fed I'd stick with 9kw as that's all triton do in the t90. Only other option for tank fed is mira elite qt 10.8kw 240v / 10kw 230 volt. This is a mod that might need replacing every 3 or 4 years due to the low build quality.

Just rereading OP again. I got sidetracked. It says pressure fluctuation when pump kicks in. I'm wondering why the pump doesn't kick in immediately? Assuming it kicks in after a few seconds then the mains fed shower will work fine.

mikeymouse

Sleeper12 wrote: »

I agree with John. 10kw mains shower, going through the pump, if it's a new installation. The if its tank fed I'd stick with 9kw as that's all triton do in the t90. Only other option for tank fed is mira elite qt 10.8kw 240v / 10kw 230 volt. This is a mod that might need replacing every 3 or 4 years due to the low build quality.

Just rereading OP again. I got sidetracked. It says pressure fluctuation when pump kicks in. I'm wondering why the pump doesn't kick in immediately? Assuming it kicks in after a few seconds then the mains fed shower will work fine.

Thanks for the replies folks,
Sorry Sleeper , maybe I didn't make it very clear.
The water comes from a bored private well, about 30 yards from the house.
The pump(It's the one on the right, with 2 pipes down into the well,not a submersible one) kicks in and pumps the water to the house.
Quote;
When the pressure reaches a preset level, which can be anywhere from 40 to 60 psi, a switch stops the pump.
As water is used in the home, pressure begins to decrease until, after a drop of about 20 psi, the switch turns on the pump and the cycle is repeated.
You'll find the pressure gauge mounted on the tank with wires leading to the switch that controls the pump.
Unquote
There is a T-off for an outside tap , then it enters a filtering system before carrying on to the boiler.
I had anticipated taking the water for the shower immediately after the filter.
But as you can see from the Quote above the pressure fluctuates when the pump kicks in.
It looks like it will have to come from the loft tank.
So I may well bring the hot water through as well and install a power shower.

Sleeper12

the idea of putting a pump on a mains electric shower is to give it constant pressure. Constant pressure gives it steady temperature. If the pressure from the pump fluctuates then so will the temperature.

Options as I see them:
9KW Triton T90SR fed from the attic. Decent quality shower giving 3 to 4.5 litres per minute
Mira Elite QT 10KW fed from the attic. Crappy shower giving 3.4 to 5 litres per minute
Hot & cold supply from the same pump from the well feeding a hot/cold mixer shower giving a better pressure shower

mikeymouse

Thank you Sleeper,
A bit more research needed , I'll probably wait for plumber to finalise plan.

Sleeper12

mikeymouse wrote:

Thank you Sleeper, A bit more research needed , I'll probably wait for plumber to finalise plan.

I'm still impressed with your electrician for picking up on something (in the plumbing end of the shower) that some plumbers would miss or not care about.

mikeymouse

Sleeper12 wrote: »

I'm still impressed with your electrician for picking up on something (in the plumbing end of the shower) that some plumbers would miss or not care about.

yeah, he's top man, much in demand around here.
you might have to wait for him, but if he gives you a date and time,
he'll be there,and his work is spot on.
Mine is a small job for him, but he'll come and do what's needed when needed.

John.G

mikeymouse wrote: »

Thank you Sleeper,
A bit more research needed , I'll probably wait for plumber to finalise plan.

"The Pump" above not suitable either to a mains electric shower or a power shower due its fluctuating pressure nature, pumps used for these purposes are all fed from a storage tank and once started will keep running at a steady pressure until interrupted by a low flow switch.

Choices are;??
Electric Shower.
Triton 9 kw tank fed.(As per sleeper12)

Power Shower(s).
1. Gravity fed from tank/HW cylinder but max head available is only ~ 0.6 bar (6M)

2. Pump fed (grundfos or stuart turner) via tank/HW cylinder. (a "real" power shower)

3. Triton AS2000XT, this has its own integral pump fed from tank/HW cylinder and will give up to 14 LPM, a much cheaper option than 2 above and IMO a very nice shower with a decent flow rate.

mikeymouse

Thanks John G,
Your option 3 is what I've got in the upstairs bathroom; Triton AS2000X I think,
and its grand.
At 14 LPM is that treble the output of the Triton 90 that Sleeper mentioned above?
If so it's a no-brainer.
Can I take the hot from the handbasin up and over the ceiling and down to the shower?
Or will that cause air lock problems, and problems if hot water is drawn elsewhere?
I know the cold has to come direct from loft tank.
Thanks again.
Mikey

g6fdyotp5nj2l7

mikeymouse wrote:

Can I take the hot from the handbasin up and over the ceiling and down to the shower?

I'm no expert so open to correction but I've always been told the hot feed must come straight from the hot water cylinder.

John.G

mikeymouse wrote: »

Thanks John G,
Your option 3 is what I've got in the upstairs bathroom; Triton AS2000X I think,
and its grand.
At 14 LPM is that treble the output of the Triton 90 that Sleeper mentioned above?
If so it's a no-brainer.
Can I take the hot from the handbasin up and over the ceiling and down to the shower?
Or will that cause air lock problems, and problems if hot water is drawn elsewhere?
I know the cold has to come direct from loft tank.
Thanks again.
Mikey

Yes, ~ treble the Triton 90, as long as there is sufficient hot water available. You may have the non thermostatic version, I think XT denotes thermostatic which would be the one to go for.

As Amstel states above, the hot water should ideally be taken direct from the HW cylinder, you would want to take care with the proper installation as you now may have two showers pulling hot water from the HW cylinder.

EDIT: On second thoughts, maybe a downstairs gravity flow only shower may give a reasonable flow rate with the proper mixing bar and shower head??.