Increase bar/flow to electric shower

[adamjth]

Hi,

I have just plumbed up a Mira Jump 10.8kW ( 0.7bar - 5bar cold mains) and the sparky came around & setup the RCD circuit. I have turned it on and whilst it functions as a shower and is right temp I am a little underwhelmed with flow esp as I have tee'd off the direct cold mains at earliest point, used only 2 x 15mm elbow to supply the shower with. I have measured the flow from shower (running cold) and its delivering 10 litres per min from the shower head (the pipework I added from cold mains was 5metres in length - so I think this is about 1 bar pressure). Also this is the same performance I get from the tap downstairts that also comes from cold water mains direct. So to my questions:-

- is this about what I should expect performance wise from this shower spec ( I guess I need to measure the flow in litres when its running at the hot temperature I need for comparison)

- are there any inline pump solutions that might help here? I see a budget pump like the Flowflex SP2B which looks easy to fit but possibly not got enough grunt

thanks

Adam

 

[oldbuffer]

1. You can't fit a pump on the mains unless it delivers less than 12 litres / minute.
2. I'd have thought 10 litres / minute for an electric shower is right at the top end of expectations.
3. 5 metres vertically upwards would lose 1/2 bar (approximately). Horizontally it would make no difference to pressure.

 

[terryplumb]

It's highly unlikely that your shower can deliver water hot enough to shower with ,at a flow rate of ten litres per minute.

 

[Madrab]

is this about what I should expect performance wise from this shower spec

Yes - probably at its coldest setting

are there any inline pump solutions that might help here

No

You shouldn't pump an electric shower. It has a set flow/pressure input controlled by the shower itself, pumping won't alter that.

Have to agree with @terryplumb - if you're @ 10L/Min then it won't be hot enough to shower in, unless you like cold showers of course.

 

[flameport]

If you want 10 litres/minute out of a 10.8kW electric shower, it will only provide a 15C rise in temperature.
If your cold water is 5C, you will be showering in 20C water.

For more normal use, such as water out at 40C, you can expect between 4 and 5 litres/minute.
The limitation is the power of the heating element.
If you want higher flow at the same temperature, you need more power.

As there are no domestic electric showers above 10.8kW, that means using some other method of heating such as a gas combi boiler.
Or heating stored water and then using that with a mixer valve.

 

[adamjth]

Thanks for various replies folks. Yes my figure of 10litres per min was with the shower set to completely cold (no heat applied) and I get that the limitation is the heating element so the flow would be lower when heat applied. So I am reading here that "it is what it is".

The only reason my expectation was higher was because I was renting a place in the next street and electric shower experience was better... excepted the model at that place was a Triton AS2000XT Thermostatic Power Shower. Which I believe is a gravity fed model but likely has built in pump hence "power shower". I went for Jump simply on the back of a "best buy" status from Which

 

[flameport]

Triton AS2000XT Thermostatic Power Shower.

That doesn't heat the water - it's just a mixer valve and a pump. The hot water would be supplied from a cylinder.

 

[Madrab]

The only reason my expectation was higher was because I was renting a place in the next street and electric shower experience was better... excepted the model at that place was a Triton AS2000XT Thermostatic Power Shower. Which I believe is a gravity fed model but likely has built in pump hence "power shower". I went for Jump simply on the back of a "best buy" status from Which

Understand the confusion - they look like an electric shower with a similar footprint but all they do is pump the hot water held in the cylinder and the tanked (cistern) cold water.

 

[adamjth]

ah...never knew that it looked so much like an electric shower... Oh well I am learning (blush)

 

[Madrab]

ah...never knew that it looked so much like an electric shower... Oh well I am learning (blush)

yep ... here's an example .... hard to tell which is which ...