Having installed a combi boiler recently we no longer have the backup of the
immersion heater in the cylinder. So we are thinking about installing an
electric shower so that at least that will continue to work should the
boiler not be working for any reason.

However since we are having to modify the bathroom to take the new shower I
would like to make regular use of it, not just in emergencies, it would
probably be best in that case for the shower to be able to run off the hot
water supplied by the boiler.. but should hot water not be available it
should be able to generate its own.

Is there such as thing as an electric shower which can use a hot water input
when it's available?

Cheers

On Wed, 05 Jan 2005 18:41:51 +0000, Mark Hewitt wrote:

Having installed a combi boiler recently we no longer have the backup of the
immersion heater in the cylinder. So we are thinking about installing an
electric shower so that at least that will continue to work should the
boiler not be working for any reason.

However since we are having to modify the bathroom to take the new shower I
would like to make regular use of it, not just in emergencies, it would
probably be best in that case for the shower to be able to run off the hot
water supplied by the boiler.. but should hot water not be available it
should be able to generate its own.

Is there such as thing as an electric shower which can use a hot water input
when it's available?

Cheers

I may be wrong but the simplest way would be to install a normal
thermostatic mixer over the bath or in a cubicle.

The cost of an electric shower is nearly all in the supply installation.

I would install the backup electric shower near the 'normal' one but
remove the outlet hose. When needed you move the hose from the mixer to
the electric unit until the boiler is fixed, keeping the same shower head
and riser rail.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
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Is there such as thing as an electric shower which can use a hot water
input
when it's available?

Well, you could run the outlet of a flush mounted thermostatic mixer through
one, but why would you?

Electric showers are ugly and seriously constrain the water flow.

If you really need a backup, consider using an inline electric water heater
on the hot feed to a standard thermostatic mixer shower setup. This way you
get nice looks, good combi performance and can just switch on the electric
(and turn down the flow) when required. Careful choice of location should
enable all the taps in the bathroom to benefit. You could even drive the
kitchen off it, although I wouldn't advise it unless the bathroom and
kitchen are close together, or you'll be waiting an age for the water to
come through. Select a good thermostatic mixer that claims compatibility
with combis, as these should be able to cope with the effect of varying
temperature on the hot side.

http://www.hygienesuppliesdirect.com...d=46&storeid=0

You could probably get away with the cheaper 7kW, as it is only an emergency
backup. You won't mind the slighter drizzle if it is saving you from having
to use the showers down the local swimming pool! On the other hand, if
you're running new cable and 30 quid means nothing to you, go for the full
9.5kW.

Have an electric shower head available. These will work better on the low
flow electric situation than a standard power shower head that you should
use when on combi power.

Christian.

"Mark Hewitt" wrote in message
...
Having installed a combi boiler recently we no longer have the backup of
the
immersion heater in the cylinder. So we are thinking about installing an
electric shower so that at least that will continue to work should the
boiler not be working for any reason.

However since we are having to modify the bathroom to take the new shower
I
would like to make regular use of it, not just in emergencies, it would
probably be best in that case for the shower to be able to run off the hot
water supplied by the boiler.. but should hot water not be available it
should be able to generate its own.

Is there such as thing as an electric shower which can use a hot water
input
when it's available?

It is best to install a normal pressure balanced mixer for the shower fed
from the combi. In the hot water line have an in-line instant electric
water heater for backup. The hot water from the combi just runs through the
heater. It will give a dribble of a shower in comparison, but get you wet
and clean when the combi is down, which should not be very long.

You can pick up the in-line heater for around £80-100.

"Christian McArdle" wrote in message
. net...
Is there such as thing as an electric shower which can use a hot water
input
when it's available?

Well, you could run the outlet of a flush mounted thermostatic mixer
through
one, but why would you?

Electric showers are ugly and seriously constrain the water flow.

If you really need a backup, consider using an inline electric water
heater
on the hot feed to a standard thermostatic mixer shower setup. This way
you
get nice looks, good combi performance and can just switch on the electric
(and turn down the flow) when required. Careful choice of location should
enable all the taps in the bathroom to benefit. You could even drive the
kitchen off it, although I wouldn't advise it unless the bathroom and
kitchen are close together, or you'll be waiting an age for the water to
come through. Select a good thermostatic mixer that claims compatibility
with combis, as these should be able to cope with the effect of varying
temperature on the hot side.

http://www.hygienesuppliesdirect.com...d=46&storeid=0

You could probably get away with the cheaper 7kW, as it is only an
emergency
backup. You won't mind the slighter drizzle if it is saving you from
having
to use the showers down the local swimming pool! On the other hand, if
you're running new cable and 30 quid means nothing to you, go for the full
9.5kW.

Have an electric shower head available. These will work better on the low
flow electric situation than a standard power shower head that you should
use when on combi power.

Now that's interesting! So this can be used to provide hot water to any
destination when the boiler is not functioning?
Presumably such an arrangement can be used to fill a bath should the boiler
fail?

In that case I might look at something like this, at present we only have a
bath and installing a shower is going to take several hundred pounds worth
of plastering and tiling work to get it fitted. If we can do without that,
all the better. Even if it's going to take half an hour to fill the bath
that's better than having no hot water at all.

The 9.5kW is just over £100, which is much less than we were looking at for
a shower installation. I take it my central heating installer should be able
to source and fit one of these units?

Presumably such an arrangement can be used to fill a bath should the
boiler
fail?

At 9.5kW, the bath will have gone cold before it has finished filling! You
can get 24kW inline heaters, which have the same output as a small combi,
but you'll need more than a single phase supply. They come in single phase
100A versions (which obviously need a phase to themselves) and 3 phase 33A
versions (which take a nibble out of each). Such a device could fill a bath.

Even if it's going to take half an hour to fill the bath that's better
than
having no hot water at all.

It would take about 45 minutes, if it stays hot enough.

Christian.

Out of curiousity, could you use on of these inline heaters to provide
a tiny bit more oomph to a shower that runs from an existing combi hot
feed? I'm presuming this wouldn't work as the inline would restrict the
water flow too much but I'd be interested to find out.

Thanks

Seri

Out of curiousity, could you use on of these inline heaters to provide
a tiny bit more oomph to a shower that runs from an existing combi hot
feed? I'm presuming this wouldn't work as the inline would restrict the
water flow too much but I'd be interested to find out.

My guess is that the inline wouldn't actually produce significant pressure
difference and could be left in line and would work as you indicate. I have
no data to back this up, though.

However, even a diddy 24kW combi should have enough for all but the most
powerful showers, such as panel types.

Christian.

"Christian McArdle" wrote in message
. net...
Presumably such an arrangement can be used to fill a bath should the
boiler
fail?

At 9.5kW, the bath will have gone cold before it has finished filling! You
can get 24kW inline heaters, which have the same output as a small combi,
but you'll need more than a single phase supply. They come in single phase
100A versions (which obviously need a phase to themselves) and 3 phase 33A
versions (which take a nibble out of each). Such a device could fill a
bath.

Even if it's going to take half an hour to fill the bath that's better
than
having no hot water at all.

It would take about 45 minutes, if it stays hot enough.

Ah bugger.. sounded like a good idea.. back to the drawing board :-(

Mark Hewitt wrote:
Having installed a combi boiler recently we no longer have the backup of the
immersion heater in the cylinder. So we are thinking about installing an
electric shower so that at least that will continue to work should the
boiler not be working for any reason.

However since we are having to modify the bathroom to take the new shower I
would like to make regular use of it, not just in emergencies, it would
probably be best in that case for the shower to be able to run off the hot
water supplied by the boiler.. but should hot water not be available it
should be able to generate its own.

Is there such as thing as an electric shower which can use a hot water input
when it's available?

I think you can get an electric in-line water heater. I haven't checked
but presumably it will let water flow if no power is applied. If not a
valve or 2 is all that's required.